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active, adj. and n.

Quotations:
Pronunciation:  Brit. /ˈaktɪv/ , U.S. /ˈæktɪv/
Forms:  ME actiff, ME actiffe, ME actijf, ME actyffe, ME actyfy, ME–15 actyf, ME–15 actyfe, ME–15 actyff, ME–15 actyue, ME–15 actyve, ME–16 actif, ME–16 actife, ME–16 actiue, ME– active; Sc. pre-17 actif, pre-17 actiue, pre-17 actyf, pre-17 actyue, pre-17 actyve, pre-17 17– active, 17 ackie. (Show Less)
Etymology:  < Anglo-Norman and Middle French, French actif (of a life or lifestyle) characterized by external acts of piety rather than by contemplation (1160 in Old French in vie active  ), (of a person) fond of activity, busy, energetic (c1370), (of a remedy) efficacious (1378), having the ability to act (14th cent.), (of a science) applied, practical (1400–3), (in grammar) active (as opposed to passive) (15th cent.), (of a debt) owed to a person (1549) and its etymon classical Latin āctīvus practical, (in grammar) active, in post-classical Latin also given to outward action as opposed to contemplative (6th cent. in activa vita   active life), generating action (from 12th cent. in British sources) < āct-  , past participial stem of agere   to act (see act v.) + -īvus  -ive suffix. With use as noun compare Old French, Middle French actif active voice (13th cent.), Anglo-Norman actif man of action (2nd half of the 13th cent.), and also post-classical Latin activum active verb (3rd cent.), element or quality of matter capable of acting upon something (1363 in Chauliac), use as noun (short for verbum activum) of neuter of classical Latin āctīvus, activus (masculine) man of action (14th cent. in a British source), activa (feminine) practical or moral philosophy (5th cent. in Augustine), active life (14th cent. in a British source, short for activa vita). Compare Catalan actiu (late 13th cent.), Spanish activo (1335), Portuguese ativo (15th cent. as actiuo, auctiuo, autiuo), Italian attivo (late 13th cent.).

Compare the following early use of the Latin word (in sense A. 3) in an English context:

OE   Ælfric Gram. (St. John's Oxf.) 120   Nu synd þa word gehatene Activa, þæt synd dædlice, þa ðe geendiað on o.
OE   Ælfric Gram. (St. John's Oxf.) 122   Ða word, þe synd passiva, beoð activa, gif se r byþ aweg gedon: armor ic eom gewæpnod, armo te ic wæpnige ðe.
OE   Ælfric Gram. (St. John's Oxf.) 218   Plecto ic gewitnige is Activvm.
 
In sense A. 13   after French moléculairement actif (J. B. Biot 1840, in Ann. de chim. et de physique 74 405).

 A. adj.
 I. General senses.
 1.

 a. Of a way or style of life: characterized by outward action rather than inward contemplation or speculation; practical. Esp. in active life, and chiefly in religious contexts. Opposed to contemplative or speculative.

1340   Ayenbite (1866) 199   Holy Writ ous tekþ tuo maneres of liue..Þe uerste is yhote workuol (actiue)..Þe oþer is yhote resteuol (contemplatiue).
c1390  (▸a1376)    Langland Piers Plowman (Vernon) (1867) A. vii. l. 236 (MED),   Actyf lyf or Contemplatyf, Crist wolde hit alse.
1402   Reply Friar Daw Topias in T. Wright Polit. Poems & Songs (1861) II. 63   There is maad mencion of two perfit lyves, that actif and contemplatif comounli ben callid, ffulli figurid by Marie and Martha hir sister.
a1425  (▸?a1400)    Cloud of Unknowing (Harl. 674) (1944) 2   Soche one..haþ..purposed him to be a parfite folower of Criste, not only in actyue leuyng, bot in souereinnest pointe of contemplatife leuing.
c1440   in G. G. Perry Eng. Prose Treat. (1921) 24   Vnto thes men itt longith som tyme to vsene werkis of mercy in actife liffe.
a1538   T. Starkey Dial. Pole & Lupset (1989) 3   But wether hyt [sc. perfection] stond in the actyve lyfe..or els in the contemplative..hyt ys not al sure.
1578   J. Lyly Euphues f. 58,   There is amongst men a trifolde kinde of lyfe, Actiue..Speculatiue... The thirde..a lewde lyfe, an idle and vaine lyfe.
a1616   Shakespeare Othello (1622) i. iii. 270   My speculatiue and actiue [1623 offic'd] instruments.
1656   T. Stanley Hist. Philos. II. v. 14   Philosophy,..concerns either action or contemplation (thence assuming two names, Contemplative and Active) the Active consisting in practise of morall Actions, the contemplative, in penetration of abstruse Physicall causes, and the nature of the Divinity.
1726   T. Ecclestone Way to Happiness 264   Love is..always working, either in the active Life for the Service of it's Beloved, or in the Contemplative, thinking of him.
1759   A. Butler Lives Saints IV. 200   He alleged that God had called him to a state in which the active and contemplative life are joined together.
1828   D. Stewart Wks. VI. 122   We are led to apply the character of activity to those whose bodily activity is the most remarkable, and to distinguish mankind into two classes, the Active and the Speculative.
1873   J. Morley Rousseau I. 71   The morbid broodings which active life reduces to their lowest degree in most young men.
1933   F. J. Sheed Map of Life xi. 108   At one end is the contemplative life, which is almost wholly direct prayer: at the other end is the active life, but this can and should be prayer also.
2000   M. Hebblethwaite in A. Hastings et al. Oxf. Compan. Christian Thought 226/1   Ignatius Loyola's ‘Spiritual Exercises’ are enthusiastically welcomed by many as a classic foundation for the spirituality of an active life.

1340—2000(Hide quotations)

 

b. Of a discipline: practical, applied; empirical, experimental. Opposed to theoretical, speculative, or contemplative. Obs.

1605   Bacon Of Aduancem. Learning ii. sig. Hh3v,   Which three parts active [sc. experimental, philosophical, magical] haue a correspondence and Analogie with the three parts specvlative.
1609   J. Dowland tr. A. Ornithoparchus Micrologus 2   Active Musicke, which also they call Practick, is..the knowledge of singing well.
1670   T. Gale Court of Gentiles: Pt. II iii. vi. 278   He [sc. Ammonius] divides it [sc. Philosophie] first into..Theoretick, or Contemplative; and Practick, or Active.
1726   R. Blackmore Disc. Gout Pref. p. xvi,   Learning is divided into contemplative and active.
1788   Gibbon Decline & Fall V. lii. 429   Botany is an active science.
1809   M. A. Shee Elements Art i. 41   When we..elevate the barren stores of inert erudition above the fruitful acquirements of active science and philosophy; we..labour under the influence of literary superstition.
1836   L. Cass Disc. Amer. Hist. Soc. 12   This is a law of our system, and extends its sway into all the departments of life, whether active or speculative. It belongs to literature, to science, and to the arts.

1605—1836(Hide quotations)

 

 2. Capable of acting upon something; originating or communicating action; spontaneous, voluntary. Opposed to passive.

a1398   J. Trevisa tr. Bartholomaeus Anglicus De Proprietatibus Rerum (BL Add.) f. 28v,   Tweyne of þese qualites ben Iclepid actiue, able to worche, hete & cooldness; þe oþir tweyne, drynesse and wetnesse, ben Iclepid passiue, to soffre.
c1443   R. Pecock Reule of Crysten Religioun (1987) 297   Whanne Reynold preisiþ Robert, þanne þer is in Reynold an actijf preising wiþ which he preisiþ Robert, and..in Robert a passyue preising wiþ which he is preisid of Reynold.
c1475  (▸?c1400)    Apol. Lollard Doctr. (1842) 14 (MED),   Þer is mani maner of cursyng. Þe first and þe warst..is dedely synne, bi þe wilk a man synning puttiþ him self out of cominyng of feiþful men..God may not autorise þat actyfe cursyng.
a1500  (▸1413)    Pilgrimage of Soul (Egerton) ii. xxiii. f. 45 (MED),   Thu were to me actiff as fire in the wode.
a1550  (▸c1477)    T. Norton Ordinal of Alchemy (Bodl. e Mus.) l. 1479 (MED),   Heat and colde be qualites actiue; moysture and drynes be qualitees passive.
1592   W. West Symbolæogr.: 1st Pt. i. 48 G.   The actiue person in Instrumentes is he which maketh the Instruments.
1611   C. Tourneur Atheist's Trag. (new ed.) v. sig. K3v,   Nor could the first Man being but the passiue Subiect not the actiue Mouer, be the maker of himselfe.
1676   M. Hale Medit. Lord's Prayer 153 in Contempl.: 2nd Pt.,   In these the Objects were innocent, and had in themselves no active solicitation to Evil.
1736   Bp. J. Butler Analogy of Relig. i. v. 84   Perception of Danger, is a natural Excitement of passive Fear, and active Caution.
1792   W. Cowper Let. 26 Jan. (1984) IV. 7   The infallible Judge of human conduct may possibly behold with more complacency a suffering than an active courage.
1876   E. A. Freeman Hist. Norman Conquest II. x. 492   The treasons of Eadwine were often passive rather than active.
1921   Amer. Jrnl. Internat. Law 15 368   The neo-Hegelian law of nature is the active agency in the future development and ultimate attainment of cultural ideals.
2005   C. Tudge Secret Life Trees xiii. 330   Some species of fig-wasp are ‘active’ pollinators, and some merely ‘passive’.

a1398—2005(Hide quotations)

 

 3. Grammar. Denoting, relating to, or using a voice of verbs in which the subject is typically the person or thing performing the action of the verb. Opposed to passive, and in some languages also middle.The active voice comprises all forms of intransitive verbs, and those forms of transitive verbs that attribute the action of the verb to the person or thing from which it proceeds.
 
In older usage verbs were classified as active only if they had a corresponding passive. Thus cut would be active since there is a passive in, for example, the grass was cut. If a verb was active in form but had no corresponding passive it was called neuter; thus a verb like appear is traditionally neuter.

a1450  (▸a1397)    Prol. Old Test. in Bible (Wycliffite, L.V.) (Cambr. Mm.2.15) (1850) xv. 57   A participle of a present tens, either preterit, of actif vois eithir passif, mai be resoluid into a verbe of the same tens and a coniunccioun copulatif.
c1450   in D. Thomson Middle Eng. Grammatical Texts (1984) 41   How many significaciones haste in the participle? Fyue: actyf, passyf, neuter, comyn, and deponent.
1530   J. Palsgrave Lesclarcissement 4   The thyrde parsonnes plurelles of verbes actyves in the frenche tonge..ende in ent.
1591   R. Percyvall Bibliotheca Hispanica Gram. sig. Cv,   Of Uerbs personals there be three kinds, Actiue, Passiue and Neuter.
1611   J. Florio Rules Ital. Tongue in Queen Anna's New World of Words 631   It [sc. si] makes the Verbe to which it is affixed to be sometimes directly Actiue..and other times Passiue or Reciprocall.
c1620   A. Hume Of Orthogr. Britan Tongue (1870) ii. x. §8   The active verb adheres to the person of the agent; As, Christ hath conquered hel and death.
1737   J. Greenwood Royal Eng. Gram. ii. xvii. 89   When the Passive Participle ends in en.., this en is frequently neglected in the Tenses of the Active Verb formed by have and had.
1765   W. Ward Ess. Gram. 59,   A verb in the active voice very frequently denotes a state which implies no real action, as for instance to suffer.
1808   L. Murray Eng. Gram. Illustr. I. iii. 308   The following sentences, which give the passive voice the regimen of an active verb, are very irregular.
1876   C. P. Mason Eng. Gram. (ed. 21) 59   We may speak of one and the same action by means either of a verb in the active voice, or of a verb in the passive voice.
1908   Mod. Lang. Notes 23 29/1   The Old English pronominal dative retained the pre-verbal position of the active voice.
1950   Eng. Stud. 31 156   It is generally said that in a sentence like His books don't sell the verb is active in form, but passive in meaning.
2003   R. Murray How to survive your Viva vi. 97   The passive voice is widely used in academic writing, the active voice less so.

a1450—2003(Hide quotations)

 
 4.

 a. Characterized by busy or lively activity; engaging or ready to engage in physically energetic pursuits; alert, lively; busy.

a1522   G. Douglas tr. Virgil Æneid (1957) iii. iv. 135   We..eftir the Troiane gys, The active gemmys and sportis gart assay.
1555   R. Eden tr. Peter Martyr of Angleria Decades of Newe Worlde iii. vii. f. 125v,   They exercyse theym selues muche in daunceinge, wherin they are verye actyue and of greater agilitie then owre men.
1600   Shakespeare Henry IV, Pt. 2 iv. ii. 21,   I were simply the most actiue fellow in Europe.
1666   S. Pepys Diary 18 June (1972) VII. 171   He being the activest man in the world.
1718   Pope tr. Homer Iliad IV. xv. 683   So strong to fight, so active to pursue.
1786   W. Cowper Let. 31 Jan. (1981) II. 471   Infirmities..which make him less active than he was.
1806   M. Lewis Jrnl. 6 May in Jrnls. Lewis & Clark Exped. (1991) VII. 215   The sorrel I obtained is an eligant strong active well broke horse.
1866   J. E. T. Rogers Hist. Agric. & Prices I. xxiii. 599   The most active seat of the trade.
1880   Manch. Guardian 16 Dec. 4/4   The market to-day has been more active than for a considerable time.
1926   J. Devanny Butcher Shop xvii. 204   His powerful and active mind kept his sex habits at a high level.
1966   Commerc. & Financial Chron. 24 Nov. 6/3   Thursday was an active day with $83,590,0 of bonds brought to the new issues market.
2006   Chicago Tribune (Midwest ed.) 1 Oct. x. 19/3   Women who want to lose baby weight should stay active.

a1522—2006(Hide quotations)

 

 b. Stock Market. Of a security: actively traded.

1841   Observer 23 Aug.,   The Shares of the Joint Stock Banking Companies have been rather more active.
1889   Times 13 Dec. 11/1   London and South African Exploration were more active than most other securities and..closed at 26¼.
1910   M. Rollins Munic. & Corporation Bonds (1915) 2   Active Bonds. Securities which are frequently bought and sold; quoted daily, or nearly so, in the newspapers or reports of the various stock exchange transactions.
1986   N.Y. Times (Nexis) 4 Dec. (Late City Final ed.) d1   American Express was active and up 1, to 60 ¾, after the stock was recommended by Morgan Stanley & Company.
2005   D. L. Scott Guide to Investing in Common Stocks iii. 63   Active Nasdaq stocks such as Nextel Communications, Starbucks, and Yahoo each have dozens of market makers that buy and sell the stock.

1841—2005(Hide quotations)

 
 5. Finance. Opposed to passive adj. 7.

 a. That functions as an asset rather than a liability; spec.  (a) (of a debt) owed to rather than by a person (now rare);  (b) (of a balance of trade) favourable; having credits greater than debits.Recorded earliest in active debt n. (a) at Special uses 2.

1606   R. Knolles tr. J. Bodin Six Bks. Common-weale vi. i. 642   The Senatours feared the registers and publike informations, which discouered euerie mans estate, and their actiue and passiue debts.
1681   J. Dalrymple Inst. Law Scotl. ii. 192   Vitious Intromission is only a Passive Title, making the Intrometter lyable to all the Defunct's Debts, passive: but is not an active Title, whereby the Intrometter can call and pursue active.
1767   J. Steuart Inq. Princ. Polit. Oecon. II. iv. i. 312   When merchants have occasion to draw and remit bills for the liquidation of their own debts, active and passive,..they met upon the exchange.
1790   E. Burke Refl. Revol. in France 333   The least likely to lean heavy on the active capital employed.
1839   Hunt's Merchant's Mag. Nov. 420   This..has one advantage to the creditor..in being capable of being negotiable before it's maturity, and thus forming part of the creditor's active capital.
1875   E. Poste tr. Gaius Institutionum Iuris Civilis (ed. 2) iii. 350   Selling the active and passive universality of the insolvent's estate..to a purchaser who became liable to the insolvent's creditors.
1931   Economist 21 Mar. 617/2   The balance of payments improves considerably in 1930 as a consequence of the active balance of merchandise trade.
1999   Business Times (Malaysia) (Nexis) 26 Oct. 4   The active balance of trade in goods amounted to 26.2 billion schillings.

1606—1999(Hide quotations)

 

 b. Of a bond: that begins accruing interest upon issue (see active debt n. (b) at Special uses 2). Cf. deferred bonds at deferred adj.   Now chiefly hist.

1834   Times 26 Aug. 5/2   Every Cortes bondholder of 100l. will have 50 per cent. active stock, bearing interest at 5 per cent.
1874   R. L. Nash Fenn's Compend. Eng. & Foreign Funds (ed. 12) 424,   66⅔ per cent. converted into Active Bonds, 5 per cent. 33⅓ per cent. into Passive Stock, bearing no interest.
1927   Washington Post 16 Jan. 21/2   A new loan of $46,335,000, which was divided into two classes of bonds; one half ‘active’, promising interest at 5 per cent from October, 1837, and the other half ‘deferred’.
1996   V. K. Aggarwal Debt Games vii. 168   The 1870 proposal called for the conversion of the London debt bonds into new active bonds (which would immediately collect interest) and deferred bonds (which would collect interest in 10 years).

1834—1996(Hide quotations)

 

 c. Of or designating a style of investment management that seeks to outperform the average returns for a given financial market by trading astutely on the basis of dedicated research.

1965   Observer 17 Sept. 8/2   It is not all that easy to beat the index... One [unit trust] that has is Hambro Abbey, which has risen by 22.5 per cent... The management is keen on active investment with a vigorous switching and ditching policy.
1977   Wall St. Jrnl. 9 Sept. 29/4   Batterymarch currently has about $925 million under management, nearly $600 million in its indexed accounts and the rest under active management.
1987   Business Week (Nexis) 21 Sept. 104   Instead of traditional ‘active’ portfolio management, in which managers seek undervalued bonds or try to forecast interest rates, institutions are setting up ‘passive’ portfolios based on one of the major bond indexes.
2003   J. Lam Enterprise Risk Managem. v. 84   Generally, active managers implement a strategy or system designed to exploit mispricing or to manage risk. The alternative is to use a passive strategy, such as investing in a market index.

1965—2003(Hide quotations)

 

 6. In operation, working; effective, functional.

1641   A. Mervyn Speech at Impeachm. Richard Bolton 1   The Gray-headed Common Lawes Funerall; and the Active Statutes death and Obsequies.
1777   G. Washington Gen. Orders 18 Dec. in Papers (2002) Revolutionary War Ser. XII. 627   The Major Generals..are to appoint an active field officer..to superintend the business of hutting.
1830   T. De Quincey in Blackwood's Edinb. Mag. Aug. 250/1   That feeling will arise more naturally when the contempt is disturbed (and, therefore, from a quiescent raised to an active force) by a counter agent.
1868   Manch. Weekly Times 16 May 4/3   That feeling is no longer active, but a trace of its former potency may still be found.
1921   Chambers's Jrnl. Apr. 262/1   A savage land of rocks and lakes and mine-slime and active and derelict mine-workings.
1951   G. L. Leffler Stock Market xii. 178   There are now 18 active trading posts.
1978   Peace News 1 Dec. 17/3   It will become an ‘active’ airfield with nuclear fighter-bombers based there.
1993   A. Arbel Exploring Interior-point Linear Programming iii. ix. 157   To read the file and make it the active file the user presses the <Enter> key.
2007   J. DeFelice Leopards Kill iii. 42,   I quick-dialed his sat phone. The system claimed the account was no longer active.

1641—2007(Hide quotations)

 
 7.
 

 a. Of a person: participating or engaging in a specified sphere of activity, esp. to a significant degree.

1643   W. Prynne Soveraigne Power Parl. ii. 28   Proclaiming divers active Members of it [sc. Parliament], (specially imployed by Both Houses, for the defence of their severall Counties) Traytors.
1655   T. Fuller Church-hist. Brit. ii. 84   An active promoter in making the East-Saxons Converts (or rather Reverts) to the Faith.
a1734   R. North Examen (1740) iii. vii. §30 524   The Contrivance at last came out of a Gray's Inn Cabal, as the Persons, active in the executory Part, make plain.
1785   T. Reid Ess. Intellect. Powers ii. ix. 276   He was one of the most active members of the Royal Society of London at its first institution.
1832   Gentleman's Mag. Dec. 567/2   His Lordship was not personally active in politics.
1901   Amer. Jrnl. Sociol. 6 830   In working toward this ultimate goal each individual should be an active participator, and anyone who is not is a mere cumberer of the earth.
1966   Listener 18 Aug. 224/1   The failure to accept the fact that teenagers are now in practice sexually active.
2005   R. Nidel World Music: Basics vi. 320   In exile she remained an active voice against the ‘disappearing’ during the military's domestic war.

1643—2005(Hide quotations)

 
 

 b. In predicative use. Of an animal or person: engaging in one's typical activity or work at a specified time, under specified conditions, etc.

1797   ‘F. Fitzgerald’ Gen. Genteel Preceptor iii. 333   [The iguana] may be domesticated: lives in the garden; is active during night; sees well in obscurity, and easily catches nocturnal insects.
1832   J. Murdock tr. J. L. von Mosheim Inst. Eccl. Hist. I. ii. ii. ii. 146   Irenaeus, who was active during the last half of this century, was born and educated in Asia Minor.
1884   Science 23 May 616/2   If animals that are active in winter throughout the north-eastern part of the United States..should be found hibernating in a mild climate like that of central New Jersey, the fact would be of unusual interest.
1929   R. A. Wardle Princ. Appl. Zool. 197   There would seem to be for each species of insect a range of temperatures between whose maximum and minimum extremes the insect is active.
1991   Hist. & Computing 3 3/2   Data on leading Bristol businessmen active between 1870 and 1914.
2005   Digital Photographer No. 31. 56/3   Mammals are slightly more difficult because most species are active at dawn and dusk.

1797—2005(Hide quotations)

 
 

 8. In the context of sexual activity: designating the partner who takes the more active part, or the role taken by this partner; spec. designating the partner who penetrates, esp. in homosexual anal intercourse. In later use also occas. associated with sadism. Opposed to passive adj. 8.

1660   J. Garfield Wandring Whore iv. 5   That abominable sin of sodomy, wherein they are both active and passive in it.
1679   tr. T. A. d'Aubigné Hell Illuminated 93   How! ye stale Fornicatour! Sodomite both Active and Passive.
1735   H. Jacob Wks. 81   The happy Moment is the same To active Man, or passive Dame.
1740   W. Beckett Pract. Surg. (Contents),   An unnatural Venereal Case, which befel a passive Sodomite, the active Person being Clapt.
1884   J. Smithson tr. F. C. Forberg Man. Classical Erotol. I. 249   What they were ashamed of was fellation. Indeed there is a certain bold audacity in playing the active part, but none in the passive one.
1958   G. M. Sykes Society of Captives v. 96   Homosexuals are divided into those who play an active, aggressive role..and those who play a more passive and submissive part.
1966   J. Trimble 5,000 Adult Sex Words 129   Master, the active partner in a Master-Slave or Discipline relationship; one who keeps another in sexual Bondage.
2002   N. Drury Dict. Esoteric 202/1   When the female partner takes the active role it is known as maithuna viparita (‘obverse intercourse’).

1660—2002(Hide quotations)

 
 9.

 a. Mil. Of military personnel: engaged in current, professional, and full-time military service, esp. as opposed to service in a reserve or auxiliary capacity. Cf. active service n. at Special uses 2.

1805   Cobbett's Polit. Reg. 5 Oct. 539/1   The force [sc. the national guard], that it will have created, though yet in repose, will even be equivalent to active troops.
1892   Appletons' Ann. Cycl. 1891 307/2   There were 60 vessels mobilized, and both the active sailors and the reserves proved their efficiency.
1915   R. E. C. Long Colours of War 10   The reservist columns stopped traffic, wound into barrack yards, and came out in uniform, mixed with active soldiers.
1954   Chron.-Telegram (Elyria, Ohio) 17 Dec. 1/5   The sweeping plan, designed to build up a long-range, strengthened military reserve while allowing a reduction in size of the active forces.
2009   Birmingham Post (Nexis) 11 May 2   Active soldiers and veterans from conflicts past deserve our unqualified respect.

1805—2009(Hide quotations)

 
 

 b. Of or designating a current and fully participating member of a group or organization.

1830   Evangelical Mag. 24 Apr. 135/3   The determination of the Society, not to admit contributors to an active membership.
1879   C. E. Clement & L. Hutton Artists of 19th Cent. & their Wks. I. Introd. p. lix,   Besides the active members there are Honorary Members.
1911   H. D. Brown Savings & Annuity Plan for Retirem. Civil-Service Employees 182   Unless the growth of the service continues at no less rate hereafter than it has in the past the proportion of superannuated to active employees must also increase.
1957   Newark (Ohio) Advocate 22 Jan. 7/1 (heading)    Pledges entertain active members of Sigma Phi Gamma.
2004   R. Intlekofer in C. L. Hutchison et al. Cancer Registry Managem. (ed. 2) ii. 13   A student member shall be a person who is enrolled in a college level curriculum,..but who does not meet the qualification for active membership.

1830—2004(Hide quotations)

 
 II. Scientific senses.

 10. Of a substance: having a (freq. strong) physiological or chemical effect on something; opposed to inert adj. 1b. Also: designating the part of a substance which is responsible for its biological or chemical effects, esp. in active ingredient.

1639   J. Shirley Maides Revenge iii. sig. E4,   Here is some of Hannibals medicine he carried alwaies in the Pummell of his sword, for a dead lift, a very active Poyson.
1646   Sir T. Browne Pseudodoxia Epidemica vi. xii. 336,   I say, a vitriolous or copperous quality; for vitrioll is the active or chiefe ingredient in Inke.
1708   J. Harris Lexicon Technicum,   A Medicine made of the most active and energetical Parts of any Ingredients.
1733   G. Cheyne Eng. Malady ii. xii. 243   Warm and active Oils and Ointments, especially the Opodeldoc.
1787   J. Collins in Med. Communications 2 372   The active ingredient..is the capsicum.
1857   D. Livingstone Missionary Trav. S. Afr. vi. 113   It contains an active poison.
1878   T. H. Huxley Physiogr. (ed. 2) 79   It is the oxygen which is the active agent.
1932   Discovery Mar. 96/2   The active substance can be extracted from the gland and chemically analysed; it is termed iodothyrin.
1959   K. H. Beyer in S. O. Waife & A. P. Shapiro Clin. Eval. New Drugs ii. 19   Some compounds are so active that no chemical or isotopic method may be suitable to follow them at pharmacodynamically effective dosages.
2008   Guardian 17 June (G2 section) 20/2   Lemon eucalyptus contains citriodiol, an active ingredient often cited as nature's answer to chemical repellants.

1639—2008(Hide quotations)

 

 11. Geol. Of a volcano: currently erupting, or likely to erupt within the relatively near future; (also) that has erupted in the historic period. Cf. live adj.1 5c.

1771   W. Hamilton Remarks upon Nature of Soil of Naples 18   This was undoubtedly a considerable lava that ran from the Solsaterra when it was an active volcano.
1830   C. Lyell Princ. Geol. I. 317   Kamtschatka, where there are seven active volcanos.
1881   Leeds Mercury 11 June (Weekly Suppl.) 1/6   One of these mountains was an active volcano, which presented a magnificent spectacle at night.
1909   A. Lloyd Every-day Japan 8   The..hot-water springs, are distributed more widely than the active volcanoes.
1954   J. F. Kirkaldy Gen. Princ. Geol. x. 116   If the volcano is active, the bottom of the crater is filled with molten or semi-congealed lava.
2007   Metro (Toronto) 21 Mar. 24/3   I've fired AK-47s in Cambodia,..hiked active volcanoes in Chile, gone spelunking in Budapest and fed crocodiles in Malaysia.

1771—2007(Hide quotations)

 

 12. Med. Designating a disease that is at a stage in which it produces pathological changes or symptoms or is infectious. Cf. remission n. 5b.

1787   W. Nisbet First Lines Theory & Pract. Venereal Dis. i. 84   The certainty of the cure is to be judged..from the absence of those symptoms of pain which mark the active state of the disease.
1829   Lancet 22 Aug. 652/2   It is no unusual circumstance for dogs to eat their own dung, when afflicted by an active disease of the nervous system.
1871   Hampshire Telegraph & Sussex Chron. 29 Nov. 3/1   The kidneys were congested and slightly enlarged, but both were free from marks of active disease.
1918   Amer. Jrnl. Nursing 18 866   We are meeting tubercular people every day whom we do not recognize as such because, unless the disease is very active, they are like others, even to the experienced eye of the physician.
1968   New Eng. Jrnl. Med. 18 Apr. 897/1   We really have a net of seven palliatively treated patients, all of whom either are dead or have active, uncontrolled disease.
2008   Irish Times (Nexis) 15 July (Health section) 16   Research in China shows that, left untreated, each person with active TB disease will infect on average 10 to 15 people yearly.

1787—2008(Hide quotations)

 
1848   A. D. Bache & R. S. McCulloh Rep. Secretary of Treasury Sci. Investig. Sugar & Hydrometers 27   Let (α) represent the molecular rotary power of an active substance; for instance, of crystallizable cane sugar.
1907   A. W. Stewart Stereochem. iii. 53   E. Erlenmeyer, jun., and A. Arnold employed an active aldehyde to resolve a racemic base.
1934   C. C. Steele Introd. Plant Biochem. iii. viii. 75   The two active forms of arabinose occur naturally.
1992   R. T. Morrison & R. N. Boyd Org. Chem. (ed. 6) iv. 129   Since optical rotation..is caused by individual molecules of the active compound, the amount of rotation depends upon how many molecules the light encounters in passing through the tube.

1848—1992(Hide quotations)

 

 14. Astron. Of the sun, or a region of it, or a part of the solar cycle: marked by the presence of (a large number of) sunspots, and typically also exhibiting energetic magnetic phenomena and enhanced emission of particles, radiation, etc. Cf. quiet adj. 7.

1882   Gentleman's Mag. Nov. 632   Thus we should have a bigger sun, a more active photosphere, and a smaller degree of resistance to its radiations.
1894   Jrnl. Franklin Inst. 137 205   The coronal streams seen during total eclipses, particularly during the active or sun-spot period, may consist of electrified particles leaving the sun.
1918   Geogr. Rev. 5 413   The weather proved characteristic of a winter period under the influence of an active sun.
1936   Sci. News Let. 11 Jan. 20/1   The sun is becoming increasingly active as measured by the great solar storms, seen as sunspots.
1980   D. Brin Sundiver iv. xii. 122   The active regions, and sunspots themselves, fade away in a matter of weeks!
2007   H. Svensmark & N. Calder Chilling Stars i. 25 (caption)    The latest of a long succession of mild intervals when the Sun was more active and cosmic rays were relatively scarce.

1882—2007(Hide quotations)

 

 15. Physics. = radioactive adj. 1.

1899   Science 3 Feb. 185/1   The substance may be fractioned until the chlorid is 200 times more active than uranium.
1938   R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) x. 120   Active isotopes that are lighter than the stable types disintegrate with emission of positrons.
1954   K. Rankama Progr. Isotope Geol. xxv. 302   The isotope 40K is the active nuclide in the series of the three neighbouring isobars, 40A40K40Ca.
2008   Wear 265 627/1   The active species must have a half-life period compatible with the duration of the measurement.

1899—2008(Hide quotations)

 
 16.

 a. Electronics. Acting as or possessing a source of electrical energy in a circuit or network.

1924   T. E. Shea Transmission Networks & Wave Filters p. ii,   A passive network is one which contains no internal sources of power. A network which contains one or more such sources of power is called an active network.
1943   Bell Syst. Techn. Jrnl. 22 269   If the network contains active elements such as vacuum tubes, the resulting current..may be due in part to the excitation of the active elements.
1989   Opera Now Aug. 69/1   You..want..a portable CD player with active (i.e. self-amplifying) speakers.
2000   D. R. Patrick & S. W. Fardo Industr. Electronics (ed. 2) iii. 72/1   This type of active device is quite different from the bipolar junction transistor.

1924—2000(Hide quotations)

 

 b. Of a radar homing system, satellite, etc.: generating as well as receiving signals. Of a satellite, space relay station, etc.: amplifying and retransmitting signals that are received. Opposed to passive adj. 9f.

1959   Adv. Astronaut. Sci. 251   Present-day long-distance communication links are compared with..links which might use passive or active satellite relay stations.
1972   Amer. Jrnl. Internat. Law 66 788   Shaddock... This missile..has an active radar homing system.
1989   Encycl. Brit. XIX. 45/2   Active satellites send out radio signals to make tracking easier and to transmit data from their instruments to ground stations or other craft.
1994   Air & Space Technol. Nov. 55/2   Newer missiles just entering service employ active seekers, essentially miniature radar transmitters and receivers that can find the target themselves.
2005   N.Y. Times (National ed.) 14 Apr. c11/4   Some companies are working on ‘active’ millimeter wave systems, which are more like radar in bouncing energy off the person being studied.

1959—2005(Hide quotations)

 
 

 17. Of a (usually computerized) mechanical system (orig. a vehicle suspension system) or its components: capable of modifying its characteristics automatically in response to feedback.See also active optics n. at Special uses 2.

1960   Diss. Abstr. 20 4610/1   Upon introducing additional information into the system, we succeed in synthesizing active ‘struts’ which are ‘soft’ with respect to road inputs and still possess considerable transient stiffness.
1971   Proc. Inst. Mech. Engin. 185 562/2   An apparent disadvantage of active suspensions as compared with the conventional passive type lies in the greater peaking of the axle response.
1987   Autosport 28 May 44/4   If Ayrton drives at a kerb..with a passive system, the whole car jumps in the air and gets unsettled, but with the active system, it just picks a wheel up and puts it back down again.
2001   I. Stewart & J. Cohen Wheelers 339   The engineers had woven an intricate framework of active struts, designed to keep the rails from flexing as the slings accelerated along them.

1960—2001(Hide quotations)

 
 B. n.
 1.

 a. A person devoted to the active life, esp. a member of an active religious order (cf. contemplative n. 1a); an active person. Also with the and pl. concord: active people as a class.

a1425  (▸?a1400)    Cloud of Unknowing (Harl. 674) (1944) 5 (MED),   Into þis day alle actyues pleynen hem of contemplatyues, as Martha did on Mary.
c1475  (▸?c1400)    Apol. Lollard Doctr. (1842) 23   Also þei [sc. two lineages in the Old Testament] tokun actifis & contemplatifis; þat sterun to vertewe be þer two maneris.
1662   Duchess of Newcastle Several Wits iv. xxxiv, in Playes Written 111   As for fortune, she may hinder the active, the like may chance, envie, spite and malice, but cannot hinder the contemplative; the like may time and opportunity.
1671   E. Phillips New World of Words (new ed.) ,   Actifs, an order of Fryars, that feed on Roots, and wear tawny habits.
1709   P. A. Motteux Camilla iii. vii. 32   Be cruel and be jealous, If safely you wou'd Rule; The Active, and the Zealous, Condemn the easie Fool.
a1779   W. Warburton Divine Legation Moses (new ed.) ix. Introd., in Wks. (1788) III. 593   The Indolent, the Active, the Sanguine, the Flegmatic, and the Saturnine have all their correspondent Theories [of morality].
1946   E. A. Peers Fool of Love vii. 118   It is as an active that Ramon [Lull] appeals to the present age most widely.
1950   A. Huxley Themes & Variations 154   Were there not then, as always, a few ardent contemplatives and actives?
1995   P. van Doorn-Harder Contemp. Coptic Nuns 200   The actives strive to imitate Christ's earthly mission of turning to the poor, the needy, and the oppressed.

a1425—1995(Hide quotations)

 
 

b. A matter related to or characterized by action. Obs.

1609   C. Tourneur Funerall Poeme 355   All his industries, (aswell in actiues, as contemplatiues).

1609—1609(Hide quotations)

 

 2. An active power or force; an element or quality of matter capable of acting upon something.In later use hist. with reference to occult science.

?a1425   tr. Guy de Chauliac Grande Chirurgie (N.Y. Acad. Med.) f. 178 (MED),   Licium is succus i. Iuyse of an herbe inspissed, temperate in actiuez [L. in activis], with humidite.
1532  (▸c1385)    Usk's Test. Love in W. W. Skeat Chaucerian & Other Pieces (1897) 91   Every active worcheth on his passive..If fyr be in place chafinge thing able to be chafed..the oon may werche, the other shal suffre.
1594   R. Ashley tr. L. le Roy Interchangeable Course iv. f. 50,   There are two sorts of Magick, thone natural, & thother superstitious. The natural in contemplating the vertues of celestial, and terrestiall things.., and applying the actiue to the passiue [Fr. appliquant les actiues aux passiues], draweth them one to another by the similitude of nature.
1647   S. Rutherford Christ Dying i. 212   If hee [sc. Satan] have power of flouds, and seas, and be a roaring Lyon, and, by reason of his sagacity and skill in the secrets of nature, can doe wonders, though no miracles, as to raise the dead, by applying actives and passives together.
a1676   M. Hale Primitive Originat. Mankind (1677) iv. v. 332   If it should be in the power of an Angel by applying actives to passives to produce an Insect.
1743   tr. H. Boerhaave Ess. Magnetical Cures 9   Galen and Pliny are calling it a Fighting and Discord..; others a Resistance, as hindering or resisting Actives to be applied to Passives.
1801   F. Barrett Magus ii. 176   He certainly performed strange things..by the application of actives to passives.
1887   A. E. Waite Real Hist. Rosicrucians xi. 290   To produce, by the application of actives to passives, many marvellous effects.
1924   A. E. Waite Brotherhood of Rosy Cross x. 286   The remedy in respect of Natural Philosophy is by..holding fast..to the doctrine of actives and passives.
2002   S. Clark in B. Ankarloo et al. Witchcraft & Magic in Europe IV. iii. 157   Dedicated to investigating nature's innermost secrets, to manipulating actives and passives and to producing rare and wonderful effects.

?a1425—2002(Hide quotations)

 
 3. Grammar.

 a. An active form of a verb.

c1450   in D. Thomson Middle Eng. Grammatical Texts (1984) 38   How knowyste a verbe passyf? That at endyth in -r and is i-formed of an actyf and bytokenyth suffryngis.
a1500   in PMLA (1935) 50 1023   A verbe neutyr qwech hath þe lettyr & þe significacyon of an actyf may haue a passyf voys in þe thrydde persone.
1530   J. Palsgrave Lesclarcissement Introd.,   The actyves have but the pronowne or substantyve before the verbe.
1582   G. Martin Discov. Corruptions Holy Script. i. 13   If passives must be turned into actives, and actives into passives, participles disagree in case from their substantives.
1612   J. Brinsley Posing of Parts f. 15,   Cannot a Verbe Neuter take r, to make it a Passiue, as Actiues doe?
c1620   A. Hume Of Orthogr. Britan Tongue (1870) ii. x. §7   Verbes of doing are actives or passives.
1751   J. Harris Hermes i. ix. 178   Even those Verbs, called Actives,..can drop their subsequent Accusative, and assume the Form of Neuters.
1760   tr. C. Batteux Princ. Transl. ii. 37   Why do we in French chuse the actives, and the Latins preferred the passives?
1825   G. Walker tr. I. J. G. Scheller Copious Lat. Gram. II. 405/2   Caleo is inserted by Sanctius as an active, without any authority but caletur, impersonal.
1884   Proc. Amer. Philos. Soc. 21 396   These participials can also be formed from absolute verbs derived from actives of but one syllable.
1929   Language 5 189   Occasionally passives are translated as actives.
1998   K. Osborne in R. L. Thomas & F. D. Farnell Jesus Crisis viii. 293   The ruler gave his answer with two separate forms of the verb, one an aorist active.., the other an aorist middle.

c1450—1998(Hide quotations)

 

 b. With the. The active voice.

a1504   J. Holt Lac Puerorum (1508) ii. sig. D.iiv,   A verbe deponente endeth in r. and hath diffinicyon onely of the actyf, as loquor.
1607   A. Willet Loidoromastix 54   Is it indeede vnlearnedly translated preacheth? Then were the Septuagints vnlearned, that so interpret the actiue in the Hebrew, tikra.
1669   Milton Accedence 20   The Active signifieth to do, and always endeth in o, as Doceo, I teach.
1751   J. Harris Hermes i. ix. 179   The species of verbs therefore remaining are the active, the passive and the neuter.
1818   E. V. Blomfield tr. A. H. Matthiæ Greek Gram. II. 710   The effect of the active consists in determining the case which it governs.
1879   W. W. Goodwin Elem. Greek Gram. (new ed.) 110   The uncontracted forms of the future active and middle of ϕαίνω..are found in Homer and Herodotus.
1933   O. Jespersen Essent. Eng. Gram. xii. 121   The subject of a passive verb is what in the active would be an object. But if in the active there are two objects, only one of them can be made the subject.
1985   R. Quirk et al. Comprehensive Gram. Eng. Lang. 163   In English, prepositional verbs..can often occur in the passive, but not so freely as in the active.
1999   Building Design 13 Aug. 40/2   As usual we converse in New Testament Greek, but I can tell his heart's not in it. He keeps substituting the aorist active for the aorist passive in his liquid verbs.

a1504—1999(Hide quotations)

 
 4. Finance.

a. Brit. A bond that begins to accrue interest upon issue. Cf. sense A. 5b. Obs.

1835   Times 15 July 3/6   The market has been flat ever since yesterday... Last Prices... Actives, 47½; Passives, 13½.
1850   Nonconformist 3 July 548/1   The Foreign Market has been very dull... Brazilian Bonds have risen to 91, Peruvian Actives are quoted at 79.
1864   Freeman's Jrnl. (Dublin) 27 Aug. 4/2   In 1834 the Spanish Government..gave for two-thirds of the amount new bonds, which were termed Five per Cent. Actives, the remaining third of the debt being discharged in what were termed ‘Passive’ bonds, and the whole of the arrears of interest in ‘deferred’ bonds.

1835—1864(Hide quotations)

 

 b. Stock Market. An actively traded security. Cf. sense A. 4b. Opposed to inactive.

1898   Galveston (Texas) Daily News 10 July 23/3   The week closed with a fair business in actives.
1911   Manitoba Free Press 6 July 14/1   C.P.R declined nearly four points and most of the actives opened 1 to 1¾ under Monday's finals.
1943   Nebraska State Jrnl. 1 Apr. 14/2   International Mercantile Marine was among the most active issues... Other actives included International Telephone.
1994   South China Morning Post (Nexis) 1 Apr. 10   The two new listings of the week continued to post great trading volume to top the actives list.
2007   A. Kuznetsov Compl. Guide Capital Markets for Quantitative Professionals iii. xvi. 410   Unlike the situation with actives, where such things are evident immediately, market data problems involving less actively traded issues can sit undetected for hours.

1898—2007(Hide quotations)

 
 5. orig. and chiefly U.S.

 a. Mil. A member of the military in active service. Freq. opposed to reserve.

1840   Daily National Intelligencer (Washington, D.C.) 1 Sept.,   The other twenty three States and three Territories should..furnish the remaining 179,200 actives and sedentaries.
1898   C. M. Andrews Hist. Devel. Mod. Europe (rev. ed.) 350   Another [measure]..divided the army into the actives, the reserves, and the landwehr.
1933   Sunday Avalanche-Jrnl. (Lubbock, Texas) 5 Nov. 6/1   France has an army of 607,000 actives and a trained reserve of 6,328,000.
1982   Aviation Week & Space Technol. (Nexis) 17 May 173   We should move toward a system where reserves provide the bulk of our forces while the actives provide the stiffening skeleton.
2006   A. H. Cordesman Arab-Israeli Mil. Forces in Era of Asymmetric Wars ii. 20   Israel has a very small active force, but if its high-quality reserves are added to its total actives, its force strength is far more competitive with its Arab neighbors.

1840—2006(Hide quotations)

 

 b. A current and fully participating member of a group or organization.

1880   Harvard Reg. May 100/2   The Club of those earlier days was little more than the protoplasm..of the present development, in which it is by no means certain the ‘honoraries’ do not find quite as much pleasure as the ‘actives’.
1930   Coe College Cosmos (Cedar Rapids, Iowa) 9 Oct. 3/2   Delta Delta Delta actives and pledges will entertain their guests at a house dance at the Delta lodge.
1988   J. P. Hoerr Wolf finally Came xviii. 508   From a ratio of 4.0 actives to each retiree, the company swung around to a ratio of 3.5 retirees to each active.
2009   Globe & Mail (Toronto) (Nexis) 30 Nov. b5   There's got to be some kind of responsibility from the actives to the retirees.

1880—2009(Hide quotations)

 

 c. Sport (chiefly Baseball and Amer. Football). Any of a (fixed) number of players on a squad who are eligible to play in a given game or season. Cf. active roster n. at Special uses 2.In many leagues, the maximum number of such players is restricted.

1931   Capital Times (Madison, Wisconsin) 6 Nov. 20/5   Arkansas' Razorbacks..had had only 22 actives on its list, while the Maroon squad..numbers 30 or more athletes.
1962   Syracuse (N.Y.) Post-Standard 21 Mar. 16/2   Coach Frank McGuire, who had only used six men Monday night, added Ed Conlin and York Larese to his actives for this game.
1994   R. F. Burk Never just Game vii. 205   AA [= American Association] teams enforced team limits of thirty reservists and twenty actives.
2007   Chicago Sun Times (Nexis) 27 Apr. a76   The Bears are unlikely to keep four running backs on the 53-man roster, and there is no way they'll dress four among the 45 actives.

1931—2007(Hide quotations)

 

 6. A substance, molecule, etc., with particular chemical or biological activity; an active ingredient. Cf. sense A. 10.

1918   W. C. M. Lewis Syst. Physical Chem. (ed. 2) I. ix. 412   Arrhenius assumes that in a solution..the active molecules or ‘actives’ only represent a very small fraction of the total sucrose molecules.
1946   E. K. Marshall in Penicillin Conf. 188   We have in the anti-malarial game hundreds of compounds of two series. We took three or four actives and mixed them together and called them aminoquinolines.
1980   Chem. Week 6 Feb. 52   We see the next thrust for sunscreen actives in skin-care creams and lotions.
2007   Observer 9 Sept. (Observer Woman) 70/1   Serum: this goes on before moisturiser... You might also need ‘actives’ to fight against ageing, fine lines, redness, dullness.

1918—2007(Hide quotations)

 

Special uses

 

 S1. Parasynthetic (in sense A. 4), as active-bodied, active-limbed, active-minded.

1647   tr. G. Wishart Hist. Kings Affairs Scotl. under Montrose xii. 102   He call'd for only twenty active bodied men of the Highlanders that were used to hunting, & very good marks-men, and commanded them to check their insolence.
1779   T. Twining Recreat. & Stud. (1882) 74   He is a searching, experimentizing, active-minded man.
1781   J. Kershaw Methodist x. 83   From ancient Scotia's hills and fertile plans, Whose blooming nymphs and active limbed swains, O'er quaking bogs with lightsome vigour run.
1837   W. Whewell Hist. Inductive Sci. I. iii. i. 154   The pleasure which..active-minded men feel in exercising the process of deduction.
1870   W. C. Bryant tr. Homer Iliad I. v. 152   There the active-limbed, Fleet Iris stayed them.
1935   Hammond (Indiana) Times 22 Nov. (Electronic text) ,   Hitler is training every active bodied man in the nation in the intricacies of war.
2005   Express (Scottish ed.) (Nexis) 6 June 29,   I am one of those people fortunate enough to be active-minded and alert and always drive with care.

1647—2005(Hide quotations)

 
 S2.
 

  active birth n. (an approach to) childbirth in which the mother is encouraged to take an active part in the progress of her labour, chiefly by being given freedom of movement and position; an instance of this.

1982   Lancet 6 Nov. 1038/1,   2750 people, over half of them midwives, and the rest mostly parents, attended the International Conference on Active Birth.
1983   J. Balaskas Active Birth i. 1   An active birth involves you giving birth through your own will and determination.
1996   S. F. Murray & D. S. V. Segura in S. F. Murray Midwives & Safer Motherhood vii. 92   There has been little mainstream interest in active birth or natural birth techniques as yet.
2007   Lancet 10 Mar. 817/2   That rally symbolised a split between professionals and women who supported active birth.

1982—2007(Hide quotations)

 
1911   U.S. Patent 1,001,222 1/2   Said organic matter is transformed into active carbon.
1972   McGraw-Hill Yearbk. Sci. & Technol. 1971 103/2   Several processes under test employ various forms of active carbon or semiactivated coke as adsorbents.
1995   D. James in E. B. Jackson Sugar Confectionery Manuf. (ed. 2) i. 2   Normally, double carbonatation is sufficient but, if required, active carbon can be added during carbonatation.

1911—1995(Hide quotations)

 
1913   U.S. Patent 1,060,673 2/1   Slight contact of air with the active charcoal often decreases its efficiency at least 50%.
1938   Thorpe's Dict. Appl. Chem. II. 319/2   Active charcoal is widely used in industry for the recovery of valuable products which exist as attenuated vapours in unadsorbable gases.
1990   Here's Health Dec. 8/2   Over 30 per cent of the German water supply contains pesticides; only active charcoal filters can remove the residues.

1913—1990(Hide quotations)

 

  Active Citizen Force   n. S. Afr. Mil. (now hist.) (originally) a division of the Union Defence Forces; (in later use) a division of the reserve forces of the South African Defence Force.

1911   Times 1 Dec. 8/2   The Active Citizen Force will consist of citizens between the ages of 17 and 25, and it is estimated that for this purpose 20,000 to 25,000 men will be sufficient.
1981   S. Afr. Panorama July 42   Only a small percentage of its members belong to the Permanent Force. The rest are servicemen or hail from the Active Citizen Force or Commandos.
2006   Fife Free Press (Nexis) 4 Aug.,   Andre flew jet fighters when he was in the South African Air Force and massive helicopters for the Active Citizen Force after that.

1911—2006(Hide quotations)

 

  active current   n. Electr. the component of an alternating current that is in phase with the voltage; cf. reactive adj. 6a.

1900   U.S. Patent 660,803 2/1   The active current is in phase with and equal to the current which is induced in the drum.
1992   RS Components: Electronic & Electr. Products July–Oct. 775/2   A monolithic regular subsystem... Consists of..a duty-cycle controllable oscillator with an active current limit circuit, an error amplifier, [etc.].
2006   A. Hughes Electric Motors & Drives (ed. 3) vii. 276   For the same torque we would expect the same active current.

1900—2006(Hide quotations)

 

  active debt   n.  (a) a debt which is owed to a person, as opposed to one which he or she owes (now rare);  (b) a debt on which interest accrues.Opposed to passive debt.

1606Active debt [see sense A. 5a].
1728   E. Chambers Cycl. at Debt,   Active Debts, are those whereof a Person is Creditor: Passive Debts, those whereof he is Debtor.
1835   Ann. Reg.1834 414/1   The active debt should continue to bear interest thenceforth at five per cent.:..the passive debt should bear no interest in the mean time.
1853   F. Baraga Dict. Otchipwe Lang. 468/2,   I collect my credits, (my active debts,) nin nandoshkamage.
1979   F. E. Perry Dict. Banking 4/1   Active Debt, a debt owed to a person.
2005   Grimsby Evening Tel. (Nexis) 18 Nov. 9   Only £156,829,907 is ‘active debt’ and is subject to an interest rate of 7.75 per cent.

1606—2005(Hide quotations)

 

  active deposit   n. Physics a deposit of radioactive material formed by the decay of a radioactive gas or emanation (emanation n. 2c).

1904   E. Rutherford in London, Edinb., & Dublin Philos. Mag. 6th Ser. 8 636   For convenience, the products in the active deposit will be termed Radium A, Radium B and Radium C, respectively.
1936   N. Feather Introd. Nucl. Physics viii. 131   Sources of radon, radiothorium and thorium active deposit..emit positive as well as negative electrons.
2002   Atmospheric Environment 36 2800/1   Two radioactive gases, both emitted by soils, are also monitored..from measurements of short-lived daughters by the active deposit method.

1904—2002(Hide quotations)

 

  active duty n. (full-time) service in the operational work of the armed forces or police, esp. as opposed to service in a reserve or support capacity; also in extended use.

1801   in A. Anderson Jrnl. Forces Secret Exped. (1802) 206   The utmost vigilance will be expected from officers in situations of active duty, whether at the out-posts, or more immediately with the army.
1898   Argosy Aug. 32   Lieutenant Carhart, whose short leave of absence had expired, returned to active duty at the fortifications.
1941   Sun (Baltimore) 5 Aug. 11/3   The recent act permitting the Secretary of War to retire those whom a board has decreed to be ‘unsuited for further active duty’.
1984   Globe & Mail (Toronto) (Nexis) 5 Oct.,   Mr. Brown is still on the police payroll and his battle to be reinstated to active duty is before the courts.
1991   Sarasota (Florida) Herald-Tribune 15 May c5/2   Now with only six months of active duty in professional baseball, Bolton's ‘career’ numbers include a 15-4 record.
2007   N.Y. Mag. 28 May 48/1   Suicide bombers, IEDs, snipers—it's little wonder that more officers are..leaving uniform as soon as the required five years of active duty is finished.

1801—2007(Hide quotations)

 
 

  active euthanasia n. the ending of a terminally ill person's life by direct intervention, such as administering a lethal dose of painkilling drugs; cf. passive euthanasia n. at passive adj. and n. Special uses.

1954   Univ. Pennsylvania Law Rev. 103 360   One might argue that..non-feasance should go completely unpunished even though active euthanasia remains punishable.
1972   Times 24 Feb. 6/4   The report..does not state clearly where passive euthanasia ends and active euthanasia begins.
2007   Independent 13 Mar. 18/2   Active euthanasia is illegal in France.

1954—2007(Hide quotations)

 

  active galactic nucleus   n. Astron. a compact region at the centre of a galaxy which emits an abnormally large amount of radiation in one or more parts of the electromagnetic spectrum.Such regions are usually hypothesized to contain supermassive black holes.

1965   Astrophysical Jrnl. 142 1086   Violent phenomena such as novae, supernovae, active galactic nuclei, formation of hot stars, turbulence, etc., excite waves (hydromagnetic) in the interstellar medium.
1992   S. P. Maran Astron. & Astrophysics Encycl. 3/1   The term active galactic nuclei (or AGN) is commonly used to mean all active galaxies, including GSOs.
2008   Nature 24 Apr. p. vii,   Blazars are the most extreme active galactic nuclei, possessing oppositely directed plasma jets emanating from accreting supermassive black-holes at near-light speeds.

1965—2008(Hide quotations)

 

  active galaxy   n. Astron. a galaxy which emits an abnormally large amount of electromagnetic radiation, spec. one containing an active galactic nucleus.

1958   Progr. Theoret. Physics Suppl. No.6. 56   If there are 106 such active galaxies, as can be inferred from radio astronomy, we have..Density of cosmic rays from active galaxies ≃ 10−18 — 10−14 cm−3.
1990   J. Gribbin & M. Rees Cosmic Coincidences (1991) vi. 165   The central ‘prime movers’ in active galaxies are, theorists believe, spinning black holes, as massive as a hundred million Suns.
2003   UFO Mag. Sept. 79/3   Quasars are believed to be active galaxies containing a black hole at their centre.

1958—2003(Hide quotations)

 

  active immunity n. Immunol. acquired immunity which is induced in an individual by exposure to an antigenic stimulus.

1897   R. Muir & J. Ritchie Man. Bacteriol. xix. 426   Active immunity is obtained by (a) injections of the organisms either in an attenuated condition or in sub-lethal doses, or (b) by sub-lethal doses of their products.
1928   L. E. H. Whitby Med. Bacteriol. ii. 16   In active immunity the defensive mechanisms of the body have been created either by a response to a previous infection or artificially by inoculation with vaccines.
1985   M. F. Myles Textbk. Midwives (ed. 10) xxviii. 485   Some weeks elapse before the baby produces an active immunity to various organisms.
2001   N. Jones Rough Guide Trav. Health i. 8   The most common method, known as active immunity, stimulates the body to make antibodies to the disease in response to a vaccination or by contracting the infection itself.

1897—2001(Hide quotations)

 

  active layer   n. Geomorphol. a surface layer of soil, overlying permafrost, that freezes in winter and thaws in summer.

1943   S. W. Muller Permafrost 5   Above the permafrost is a layer of ground that thaws in the summer and freezes again in the winter. This layer represents the seasonally frozen ground and is called the active layer.
1977   A. Hallam Planet Earth 89   The churning of the active layer by freezing and thawing prevents the development of a stable soil structure.
2005   New Yorker 25 Apr. 61/1   When you walk around in the Arctic, you are stepping not on permafrost but on something called the ‘active layer’.

1943—2005(Hide quotations)

 
 

  active learning an educational approach in which students are encouraged to engage with the material to be studied through activities, such as experimentation, group discussion, and role-play.

1919   P. Munroe Cycl. Educ. 1 144/2   ‘Learning by doing’. This is the characteristic mode that the principle takes in the ‘active learning’ of the kindergarten.
1961   Times 2 Dec. 5/3   Call for ‘active learning’... Children should be allowed to gain knowledge at their own rate and from their own interests.
2004   J. Ciaccio Totally Positive Teaching vii. 137   In high-intensity active learning, the students are the workers.

1919—2004(Hide quotations)

 

  active list   n.  (a) a list of officers in the armed forces liable to be called on for service; also in extended use; cf. retired list n. at retired adj. and n. Compounds;  (b) = most active list n. at most adj., pron., n., and adv. Special uses;  (c) = active roster n.

1827   Morning Chron. 17 July 3/3   The Lord High Admiral has..given them their proper place of seniority in the active list of Admirals.
1857   N.-Y. Daily Times 22 Apr. 8/5   The stock has not been more largely oversold than half-a-dozen other Railroad shares on the active list.
1880   St. Louis (Missouri) Globe-Democrat 28 Mar. 3/3   The Jefferson City Base Ball Club..has reorganized for the coming season. The active list consists of the following players.
1906   Harmsworth Encycl. VII. 576/2   No officer on the active list is allowed to leave the United Kingdom without special permission.
1907   Jrnl. Soc. Arts 55 429/1   Of these only the Remington and the Hammond are to-day on the active list.
1985   Times 18 July 21/6   British Telecom returned to the active list with a spectacular 3,128 total of trades.
1998   Chicago Tribune 28 Nov. iii. 2/2   The decision on whether Bears quarterback Erik Kramer finishes the season on the active list or goes on the injured reserve might be made this weekend.
2007   Western Mail (Cardiff) (Nexis) 17 Nov. 26   He retired from the active list as a Commander.

1827—2007(Hide quotations)

 

  active mass   n.  [after French masse active ( C. M. Guldberg & P. Waage Études sur les affinités chimiques (1867) ii. §5.6)] Chem. the molar concentration of a substance taking part in a reaction (to which, by the law of mass action, the rate of the reaction is proportional); cf. mass action n. (a) at mass n.2 Compounds 2.

1879   London, Edinb., & Dublin Philos. Mag. 5th Ser. 8 183   The force causing the formation of A′ and B′..is proportional to the product of the active masses of A and B.
1955   J. C. Giblin Qualitative & Volumetric Anal. (ed. 2) iv. i. 88   The product of the active masses of hydrion and hydroxylion..is known as the ‘Ionisation Constant’ for water.
2008   A. Tuck Atmospheric Turbulence 144   In a homogeneous system the rate of a chemical reaction is proportional to the active masses of the reacting substances. Active mass is usually taken as molecular concentration.

1879—2008(Hide quotations)

 

  active matrix   n. Electronics a liquid crystal display in which each pixel can be individually refreshed, typically by means of its own transistor or diode, giving improved image quality; freq. attrib.; cf. passive matrix n. at passive adj. and n. Special uses.

1975   T. P. Brody et al. in IEEE Trans. Electron Devices 22 740/1   The difficulties and limitations of passive matrix-addressed displays..have led us to explore ‘active’ matrixes, i.e., matrixes which contain gain-producing and switching elements at their points of intersection.
1984   Fortune 28 May 76/3   While laboratory samples of active-matrix screens exist..the production process is still a question mark.
2005   N.Y. Times (National ed.) 5 May c10/4   These monitors, which have active-matrix T.F.T. (thin film transistor) screens with a native resolution of 1,280 by 1,024, can also be viewed from a 160-degree viewing angle.

1975—2005(Hide quotations)

 

  active obedience n.  (a) Theol. Christ's perfect and complete deference to God in carrying out his laws and commands, as distinguished from his suffering and dying on the cross;  (b) (voluntary) proactive compliance with the commands of an authority (opposed to passive obedience n. at passive adj. and n. Special uses).

1597   W. Perkins Reformed Catholike 64   The righteousnesse of Christ, which consisteth partly in his sufferings, and partly in his actiue obedience in fulfiling the rigour of the law.
1669   J. Stewart Jus Populi Vindicatum i. 20   Passive subjection to unjust laws and punishment, where there is power to make active violent resistance, is a greater sin then active obedience to unlawful commands of Magistrats.
a1708   W. Beveridge Thes. Theologicus (1711) III. 328   As by Christ's passive obedience we are freed from the guilt of sin, so by His active obedience we are invested with righteousness.
1890   J. Russell tr. R. de Guimps Pestalozzi, Life & Wks. 238   The first manifestations of obedience are of a purely passive character... It is not till much later that he [sc. the child] is capable of active obedience.
1955   J. Murray Redempt. Accomplished & Appl. 220   The two distinct aspects of our Lord's vicarious obedience... The law of God has both penal sanctions & positive demands... The passive obedience refers to the former and the active obedience to the latter.
2001   R. Williams in J. H. Newman Arians 4th Cent. Introd. p. xxviii,   There is a significant distinction between active obedience, co-operating with the demands of authority, and passive obedience, being subject to the laws when they require a penalty for non-co-operation.

1597—2001(Hide quotations)

 

  active optics n. Astron. an automatic system for keeping a reflecting surface in a telescope free from distortion due to gravity or other environmental effects, using small pistons which continuously adjust the position of each part of the surface; cf. adaptive optics n. at adaptive adj. Special uses.

1968   H. J. Robertson in Symp. Support & Testing Large Astron. Mirrors 245 (title)    Active optics for large orbiting astronomical telescopes.
1987   Times (Nexis) 28 Dec.,   Its main telescopic imaging system is reported to have a ground resolution of about six inches, mainly due to the incorporation of an advanced technology known as active optics.
2002   Wired Nov. 174/2   To keep the segments aligned, he used dozens of tiny computer-controlled actuators, or pistons—an innovation known as active optics.

1968—2002(Hide quotations)

 

  active-passive adj. Grammar of or designating a verb used intransitively with passive meaning; cf. activo-passive adj. 2.

1859   S. Barrett Princ. Gram. (rev. ed.) 103   The old-time division of the verb into six classes, active transitive, active intransitive, neuter trans., neuter intrans., active passive and neuter passive is now disregarded.
1950   Eng. Stud. 31 156   It is generally said that in a sentence like His books don't sell the verb is active in form, but passive in meaning, what is ‘really’ meant being His books are not sold. In accordance with this theory verbs used in this way are sometimes called active-passive or passival.
2001   Language 77 625/1   They are a linguistically natural phenomenon serving some communication need as basic as that conveyed by better known grammatical forms such as causatives, applicatives, and active-passive constructions.

1859—2001(Hide quotations)

 

  active roster   n. U.S. Sport (chiefly Baseball and Amer. Football) the list of players who are eligible to play in a given game or season (cf. sense B. 5c).

1915   Chicago Tribune 15 June 15/2   The release of Hess reduces the active roster to twenty players. This does not include Evers and Martin, who are on the disabled list.
1965   Salina (Kansas) Jrnl. 20 Dec. 10/3   Baltimore also put George Haffner on the active roster as a reserve quarterback for the Rams game.
2008   D. Moore It's Possible! 68,   I wondered why I had been placed on the practice squad. I truly believed that I..had earned the right to a spot on the active roster.

1915—2008(Hide quotations)

 

  active service n. direct participation in military operations as a member of the armed forces; cf. active duty n.

1658   W. Sanderson Compl. Hist. Life King Charles 1084   Whilst the General, Lieutenant General, Major General, Commissary General, and the most of the chiefest Commanders are abroad in active service, others are encouraged thereby.
1755   C. Chauncy Let. to Friend Ohio Defeat 21   One full eighth part of our people..are in active service at this day, and a greater number of them in our own pay.
1838   Navy List 20 Sept. 118   Alphabetical List of Masters. Those in Italics are unfit for active Service.
2002   G. McCafferty They had no Choice xix. 105   My son had previously, on several occasions, offered himself for active service, but on account of defective eyesight and varicocele, he had been rejected.

1658—2002(Hide quotations)

 

  active site   n. Chem. and Biochem. a location on a surface, molecule, etc., which possesses specific catalytic or other chemical activity; spec. the part of an enzyme or other protein molecule which binds to a substrate and participates directly in a reaction.

[1941   Proc. Royal Soc. A. 178 438   This increase is not due to a variation in the nature of the catalytically active sites.]
1945   Biol. Bull. 88 265   At the higher concentrations of azide the inhibitor could compete successfully for an active site on the enzyme surface.
1957   Jrnl. Amer. Chem. Soc. 79 2657/1   The substrate is assumed to be absorbed with a precise fit into an area called the ‘active site’ of the protein.
1993   Dog World Nov. 29/1   Selenium is the major component of the active site of the enzyme glutathione peroxidase.
2007   M. Nelson & X. D. Chen in G. Stracher Geol. Coal Fires iv. 56/1   The adsorption and desorption of water changes the number of active sites that are available for the oxidation process to occur.

1945—2007(Hide quotations)

 

  active transport n. Biochem. the transport of molecules or ions across a cellular membrane against an electrochemical gradient, typically assisted by enzymes and using energy from the hydrolysis of ATP.

1937   Trans. Faraday Soc. 33 912   Active transport of a substance is brought about by some kind of dynamic machinery working within living cells.
1964   G. H. Haggis et al. Introd. Molecular Biol. vi. 155   Movement against the concentration gradient or, more generally, movement of the transported molecule or ion to a state of higher thermodynamic potential energy, is termed active transport.
1989   Sci. Amer. Nov. 51/3   Concentrations of micronutrients in blood plasma are usually low; to scavenge them from the blood, the choroid plexus relies on active-transport mechanisms.
2005   A. J. Tobin & J. Dusheck Asking about Life (ed. 3) iv. 86/2   In active transport, cells use the energy of ATP to move ions across the membrane.

1937—2005(Hide quotations)

 

  activewear n. orig. U.S. casual, comfortable clothing, esp. in styles suitable for sport or exercise; sportswear.

1924   N.Y. Times 10 Aug. 10 e/4   Line checks in bright shades upon medium grounds are preferred for active wear, with pastel and ivory grounds prevailing in party frocks.
1984   Sears Catal. 1985 Spring–Summer 41   Laundered-look cotton activewear bursting with casual character and comfort.
2006   Guardian (Nexis) 22 Apr. (Weekend section) 73   High street specialist Blacks has just launched..its first range of women's activewear, which includes hooded tops, T-shirts and shorts in supersoft wickable fabrics.

1924—2006(Hide quotations)