From the second edition (1989):
arm, n.1
(ɑːm) Forms: 1– arm, 1–3 (WS.) earm, 2–3 erm, (eorm), 3 ærm, (Orm.) arrm, arum, 4–7 arme. [Common Teutonic: cf. OS. arm, OFris. arm, erm, OHG. aram, arm, ON. armr, Goth. arms:—OTeut. *armoz, cogn. w. L. armus shoulder; cf. Gr. ἁρµός joint, Skr. īrmas, f. Aryan root ar- to fit, join.]

I. The limb.

1. a. The upper limb of the human body, from the shoulder to the hand; the part from the elbow to the hand being the fore-arm.

c950 Lindisf. Gosp. Luke ii. 28 He onfeng him on armum his. 1123 O.E. Chron. (Laud MS.) Se kyng‥alehte hine betwux his earmes. c1200 Ormin 7616 [He] himm toc bi~twenenn arrmess. 1205 Lay. 28035 Þat mi riht ærm to-brac. Ibid. 2233 He heo mid armen i-nom. c1220 Ureisun in Cott. Hom. 213 Mi leofmonnes luft erm halt up min heaued. a1300 Havelok 2408 Smot him þoru þe riht arum. 1377 Langl. P. Pl. B. xiv. 241 Hondes and armes of a longe lengthe. 1489 Caxton Faytes of Armes i. ix, Heue vp his armes for to smyte edgelyng. 1611 Shakes. Cymb. ii. iv. 101 She stript it from her Arme. 1785 Cowper Task iv. 222 The basket dangling on her arm. 1802 Paley Nat. Theol. viii. (1827) 455 The fore-arm‥consists of two bones lying alongside each other, but touching only towards the ends.

b. as a measure of length.

1572 J. Bossewell Armorie ii. 86 Popiniayes‥exceedinge in lengthe an arme and an halfe.

2. phr. a. arm-in-arm (improperly arm-and-arm): said of two persons, when one interlinks his arm with the other's, that they may walk close together; hence fig. in close communion. Also attrib. (So humorously arm-in-armly.) to give or offer one's arm (to): to allow or invite a person to walk arm-in-arm with one, or lean on one's arm. to take the arm is to accept this invitation. a child, baby, or infant in arms: one that cannot yet walk, and has to be carried. with open arms: with eager welcome. †his arms! an obsolete oath.

c1374 Chaucer Troylus ii. 1067 They wenten arme in arme yfere Into the gardyn. a1553 Udall Roister D. ii. i, Then, his armes and woundes! I woulde not haue slacked for ten thousand poundes. Ibid. iii. iii, Armes! what dost thou? 1591 Harington Ariosto's Orl. Fur. xlvi. xxxv, Don Leon arm in arm Rogero led. a1600 Hooker Serm. i. III. 590 Continually to walk arm in arm with angels. 1735 Pope Prol. Sat. 142 With open arm receiv'd one Poet more. 1743 H. Walpole Lett. to H. Mann 67 I. 246 A clerk who had observed them go out together so arm-in-armly. 1781 Cowper Charity 314 Philosophy‥Walks arm in arm with Nature all his way. 1819 Keats Let. 24 Sept. (1958) II. 215 A child in a[r]ms was passing by his chair toward the mother, in the nurses a[r]ms. 1837 Carlyle Fr. Rev. II. ii. iv. iii. 10 A thickset Individual‥arm-and-arm with some servant. 1848 Thackeray Van. Fair lxvii. 618 You are no more fit to live in the world than a baby in arms. 1862 Sat. Rev. 633 Brummel‥replied, ‘I did my best for the young man; I gave him my arm down St. James' Street.’ a1885 Mod. She took the proffered arm. Children in arms free. 1937 E. Garnett Family from One End St. viii. 146 All the children went half price, the younger ones, with luck, ‘in arms’. 1958 G. Barker Two Plays 65 Why, even a Kelk'd be kissing itself This arm-in-arm evening. 1978 N.Y. Times 30 Mar. b3/1 Arm-in-arm couples.

b. at arm's end (obs.), at arm's length: as far out or away from one as one can reach with the arm; hence, away from close contact or familiarity, at a distance; spec. in Law, without fiduciary relations, as those of trustee or solicitor to a client; (at) arm's length: Comm., designating a sale or transaction in which neither party controls the other. to work at arm's length: awkwardly or disadvantageously. within arm (or arm's) reach: so as to be reached by a movement of the arm only. to make a long arm (colloq.): to reach out the arm a long way after something; see also long a.1 1c. as long as one's arm: colloq. for ‘very long’.

1580 Sidney Arcadia (J.) Such a one as can keep him at arms end, need never wish for a better companion. a1652 Brome Crt. Beggar i. i, A man May come within his arme~reach of his money In the Exchequer. 1655 W. Gurnall Chr. in Arm. xiv. (1669) 108/1 The Moabites could not give Israel the fall at arms-length. 1669 Penn No Cross xiii. §18 Live loose to the World, have it at Arm's-End. a1704 T. Brown Praise Pov. Wks. 1730 I. 96 No Penelopes‥to keep importunate suitors at arms-end. 1714 Swift Pres. State Aff. Wks. 1755 II. i. 220 To stand at arm's length with her majesty. 1846 J. F. Cooper Redskins (1888) xii. 198 Leases as long as my arm, I calcerlate? 1856 Kane Arct. Exp. II. vii. 79 Wood‥piled within arm-reach. 1857 H. Melville Confidence-Man vi. 39 A fellow with a face as long as my arm. 1858 Ld. St. Leonards Handy-bk. Prop. Law vi. 35 Unless there is perfect fair-dealing, and the dealing is, as it is termed, at arm's-length, it would not be allowed to stand. 1860 Trollope Framley P. (1861) II. i. 9 God be with the good old days when I could‥make a long arm for a hot potato whenever the exigencies of my plate required it. 1879 T. Lewin Trusts (ed. 7) 441 The parties must be put so much at arm's length that they stand in the adverse relations of vendor and purchaser. 1884 Daily News 26 Jan. 6/2 Monkeys‥making long arms‥for stray beans or sweetmeats. 1938 M. Allingham Fashion in Shrouds xx. 370 Jock has a record as long as your arm. 1961 Webster, Arm's length, the condition or fact that the parties to a transaction or negotiation are independent and that one does not dominate the other (sale at arm's length) (arm's length bargaining). 1962 Taxation of Short-Term Gains (Cmnd. 1710) 9 Where an asset changes hands as a result of a bargain which is not at arm's length (i.e. generally speaking, at an artificial price) it is normally deemed to pass for its then market value. 1962 Economist 8 Dec. 1040/1 Some [companies]‥are‥‘arm's length buyers’ of imported crude wherever—and as cheap as—they can get it.

c. Slang phr. under the arm: inferior, poor, bad.

1937 in Partridge Dict. Slang 17/1. 1958 F. Norman Bang to Rights 31, I read no matter how bad the book and some are right under the arm, stand on me. 1963 New Statesman 18 Oct. 537/1 All that's under the arm (i.e. no good).

3. fig. a. Might, power, authority. secular arm: the authority of a secular or temporal, as distinguished from an ecclesiastical, tribunal.

c950 Lindisf. Gosp. John xii. 18 Arm drihtnes huæm is ædeaued [Rushw. eorm]. 1382 Wyclif ibid., To whom is the arm of the Lord schewid? 1535 Coverdale Ezra iv. 23 And forbad them with the arme and auctorite. 1611 Bible Ezek. xxx. 21, I haue broken the arme of Pharaoh. 1782 Priestley Corrupt. Chr. II. ix. 145 The relapsed [are] delivered to the secular arm. 1831 Brewster Newton (1855) II. xviii. 186 No period of his life can be named when his intellectual arm was shortened.

b. That on which one relies for support or assistance; a prop, support, stay. right arm: main stay, chief executive agent.

1382 Wyclif Jer. xvii. 5 Cursid the man that trostith in man, and putteth flesh his arm. 1535 Coverdale ibid., That taketh flesh for his arme. 1859 Tennyson Guinevere 426 Sir Lancelot, my right arm, The mightiest of my knights.

c. in fig. expressions that attribute arms (in various relations) to things that have none.

1597 J. Payne Royal Exch. 7 He reserved neither legg nor arme of that lyvinge to hym self. ?a1700 Sir Patrick Spens, I saw the new moon, late yestreen, Wi' the auld moon in her arm. 1850 Tennyson In Mem. xxi. 18 Science reaches forth her arms To feel from world to world. 1866 B. Taylor Mariners 290 Cradled in the arms of the tide.

4. a. The fore limb of an animal: said, popularly, of apes, bears, and other animals that rise on their hind legs; in scientific use, of any of the mammalia.

1607 Topsell Four-f. Beasts (1658) 3 Apes‥have‥their breasts and armes like men, but rougher. 1781 Smellie Buffon's Nat. Hist. (1785) V. 14 The bear‥has fleshy legs and arms. 1847 Carpenter Zool. §90 The arm and the thigh each present, among all the Mammalia, but one bone. Ibid. §330 In Birds‥the conformation of the arm and fore-arm differs little from that of the same parts in man.

b. Falconry. The leg of a hawk from the thigh to the foot.

1575 Turberv. Falconrie 8 This Eagle Royall‥hath not hir armes or feete in any condition couered with plume as the Vulture hath. 1678–1706 in Phillips and in mod. Dicts. under arm(s n.2

c. The flexible limbs or other appendages of invertebrate animals; as the locomotive and prehensile organs of cuttle-fish, the tentacula of the hydroid polypes, the rays of star-fish, etc.

1822 Burrowes Cycl. IX. 786/2 the Cuttle-Fish‥besides eight arms has two tentacula longer than the arms. 1867 Carpenter Zool. §1043 In the Hydra, the arms vary in number, being usually from six to ten. Ibid. §1044 When in search of prey, the Hydra permits its arms to float loosely through the water. 1870 Nicholson Zool. xix. (1880) 201 The body [of Star-Fishes]‥consists of a central‥‘disc’ surrounded by five or more lobes or ‘arms.’

5. The part of dress covering an arm; a sleeve.

a1797 H. Walpole George II (1847) III. i. 8 The right arm lined with fur. 1831 Carlyle Sart. Res. iii. vi, The Coatarm is stretched out.

II. Things resembling arms.

6. A narrower portion or part of anything projecting from the main body. a. In arm of the sea, of ancient use, and quite transferred. b. Also of the land (obs.), a mountain (fig.).

c885 K. Ælfred Oros. i. i. §28 On oþre healfe þæs sæs earmes is Ibernia. 1538 Leland Itin. VII. 143 The Marsch Land‥runnyng ynto a Poynt standeth as an Arme, Foreland, or Nesse. 1598 Hakluyt Voy. I. 65 The Great sea, out of which the arme of S. George proceedeth. 1724 De Foe, etc. Tour Gt. Brit. (1769) III. 60 That Arm of the Sea which is now called the Humber. c1854 Stanley Sinai & Pal. Introd. (1858) 53 The arms of the mountain closing us in.

c. of a machine, or other object.

1833 Brewster Nat. Magic v. 110 On a projecting arm‥I fixed a broad collar. 1881 Greener Gun 18 The powder-chamber or arm of the bombard is of much smaller diameter.

7. One of the branches into which a main trunk divides.a. spec. of a vine. Obs. b. fig. A main branch or limb of any tree (usually with something of personification).

1398 Trevisa Barth. De P.R. xvii. cxvi, ‘Palmes’ is propirly a bowe oþer a spray of a vine, and‥spryngeþ oute in newe armes. 1580 Lyly Euphues (Arb.) 473 They that feare theyr Vines will make too sharpe wine, must not cutte the armes. 1579 Spenser Sheph. Cal. Feb. 104 A goodly Oake‥With armes full strong. 1611 Cotgr., Avantin, the arme, or braunch of a vine. 1697 Dryden Virg. Georg. iii. 514 Some ancient Oak, whose Arms extend In ample Breadth. 1863 Longfellow Falc. Federigo 5 A huge vine‥with its arms outspread.

c. of a river, a nerve, or the like.

1330 R. Brunne Chron. 67 His flete alle pleyn In an arme of Ouse vnder Ricalle lay. 1601 Holland Pliny I. 118 The great riuer Tanais, which runneth into Mœotis with two armes or branches. 1846 Grote Greece xx. II. 490 The Pelusian arm of the Nile. 1870 Rolleston Anim. Life 132 An azygos nerve trunk‥which‥has two lateral arms.

8. One of two lateral (and generally horizontal) parts, which answer to each other, like the two arms of the body. a. Naut. (a) The parts of an anchor, at right angles to its shank, which bear the flukes that grip the bottom. (b) The parts of the yard extending on either side of the mast; see yard-arm. (c) ‘The extremity of the bibbs which support the tressel trees’ (Smyth Sailor's Word-bk. 1867).

1665 Pepys Diary 18 Sept., The yard-arms sticking in the very rocks. 1706 Phillips, Arm of an Anchor, that part of it to which the Flook is set.

b. of machines; as of a balance. In a lever: The part or length from the fulcrum to the point of application of the power or weight respectively. (In levers of the second and third kind, the power arm and weight arm are both on the same side.)

1659 J. Leak Water-wks. 17 The said Levers shalbe also fitted to two arms or branches. 1727–51 Chambers Cycl. s.v. Crane, The middle and extremity of this [beam] are again sustained by arms from the middle of the arbor. 1866 Newth Nat. Phil. (1873) 34 It is convenient to describe the perpendiculars drawn from the fulcrum to the directions of the power and the weight as the power's arm and the weight's arm respectively.

9. One of the two rails or projecting supports at the sides of a chair, sofa, etc., on which the arms of one who is using it may rest. See arm-chair.

1633 [See arm-chair]. 1859 Tennyson Elaine 437 Two dragons gilded, sloping down to make Arms for his chair. 1882 J. Hawthorne Fort. Fool xiv, The chairs and sofas having curved and arabesqued backs, legs, and arms.

III. Comb. and attrib., as arm-badge, arm-eddre (= vein), arm-glove, arm-linked, arm-sweep, arm-twister, arm-wrist. Also arm-band, a band worn round the arm; arm-bone, the bone of the arm, the humerus; †arm-circle, arm-coil, a bracelet, an armlet; arm-cylinder, a cylindrical ornament worn on the arm; †arm-gaunt a., (meaning not certainly known) ? with gaunt limbs; †arm-great a., as large round as an arm; arm-guard, (a) in Boxing, defence with the arm; (b) a protective covering for the arm; †arm labour, manual labour; arm-lock, a close hold by the arm in wrestling and judo; also v. trans. (nonce-wd.); arm-piece, armour to protect the arm; arm-rest, a device constructed for the arm to rest upon; arm-ring, an ornamental ring worn on the arm; an armlet; †arm-slasher, one who cuts his arm to get blood with which to drink his mistress' health; †arm-strong a., strong of arm; arm-twisting (orig. U.S.), (persuasion by) the use of moral pressure, force, or threats of physical violence (cf. twist v. 9e); arm-wrestling = wrist-wrestling s.v. wrist 5d; also arm-wrestle v. intr., to engage in arm-wrestling. See arm's-end, -length, arm-reach, under 2b. Also arm-chair, -hole, -pit, armful, armless, q.v.

1931 A. P. Herbert Derby Day iii, The policeman's helmet and *arm-badge are on the table as he is off duty. 1797 B. Hawkins Let. 26 Nov. (1916) 253 The goods he wants are‥3 pair *arm bands, 3 pair wrist bands. 1846 T. L. McKenney Memoirs I. 178, I opened a box and took out a pair of silver arm-bands. 1906 Yorks. N. & Q. III. 101/1 A fragment of a jet arm-band was found on the same horizon. 1922 D. H. Low tr. Ballads of Marko Kraljević 135 On his feet two fetters, On his arms two armbands. 1952 Manch. Guardian Weekly 21 Feb. 5/1 After them came the Sheffield's officers, in white uniforms with black armbands. a1639 Abp. Spotiswood Ch. & St. Scotl. (1677) 5 The *Arm-bone, three Fingers, and as many Toes of St. Andrew. 1851 Richardson Geol. viii. 308 In the anterior extremities we find an arm-bone. 1382 Wyclif Ecclus. xxi. 24 As an *arm-cercle in the riȝt arm. 1866 Livingstone Jrnl. iii. (1873) 68 *Arm-coils of thick brass wire. 1937 Antiquity XI. 114 The axes, dagger, and *arm-cylinder of the Danish hoard. 1957 Childe Dawn Europ. Civ. (ed. 6) v. 69 From Asia came an arm-cylinder of twisted silver wire (like a gold one from Troy II) found in a grave on Levkas. c1230 Ancr. R. 258 Hwon heo beoð ileten blod on one *erm eddre. 1606 Shakes. Ant. & Cl. i. v. 48 Did mount an *Arme-gaunt Steede. 1816 Scott Old Mort. xi, Mounted upon his arm-gaunt charger. 1740 C'tess of Hertford Corr. (1806) II. 127 Black velvet *arm-gloves. c1386 Chaucer Knt.'s T. 1290 A wreth of gold *arm-gret. c1420 Pallad. on Husb. iii. 412 An *arme greet withi bough. 1889 Michell Boxing 148–9 Figure ix, Left *arm guard. Ibid. 156 Right arm guard. 1899 Daily News 20 June 3/5 Two massive gold arm-guards, set with‥diamonds. 1677 A. Yarranton Engl. Improv. 185 Will draw more Wire in one day, than six men can‥by *arm labour. 1839 Bailey Festus vi. (1848) 53 A shadow not thine own *armlinked with mine. 1905 A. M. Binstead Mop Fair vi. 102 Whose simple faith in all mankind has been mercilessly *arm-locked and thrown clear off the mat. 1905 F. R. Toombs How to Wrestle (1906) 61 (caption) The Near Leg Hold and Arm Lock. 1956 K. Tomiki Judo 127 Kansetsu-waza‥ude-hishiji (armlock) and ude~garami (entangled armlock). 1844 Marg. Fuller Wom. in 19th C. (1862) 86 A golden helmet and *arm-pieces. 1889 Cent. Dict., *Arm-rest. 1898 Sloane Stand. Elect. Dict. App., Arm rest, a device for lessening the fatigue of holding a telephone receiver to the ear. 1908 Daily Chron. 12 Mar. 5/6 The deceased's head was‥over the mouth of the barrel, which was leaning against the arm-rest. 1962 Which? (Suppl.) July 91/2 This measurement excludes the permanent centre armrest in the two sports cars. 1903 W. B. Yeats In Seven Woods 49 I'll give you gifts, but I'll have something too An *arm~ring or the like. 1933 E. E. Evans-Pritchard Ess. Social Anthrop. (1962) vii. 143 Azande‥made a pact by drinking water from a gourd which contained an iron arm-ring. 1611 Cotgr., Taille-bras, A hackster, *arme-slasher. c1000 Ælfric Gloss. in Wright 43 Torosus, *earm-strang. 1589 Greene Menaphon (Arb.) 56 Alcides, the arme-strong darling of the doubled night. 1850 Mrs. Browning Poems II. 276 Like a fly‥By queen Juno brushed aside, a Full white *arm-sweep, from the edge. 1938 New Statesman 8 Jan. 58/2 A great *arm-twister, and the sort of man who ought never to have been born. 1967 K. Giles Death in Diamonds ix. 164 A brute and a bully, an arm-twister and a threatener. 1957 Newsweek 30 Dec. 31/3 *Arm twisting is used to induce ‘wavering elements, petty bourgeois, and the non-productive’ to sign ‘voluntary petitions’ for rural service. 1963 W. H. Missildine Your Inner Child of Past xi. 106 We are so accustomed to overly coercive attitudes that arm-twisting, demanding commercials on television and anxiety-arousing articles in the press seem right to us. 1984 Listener 23 Aug. 9/1 Diplomatic pressure‥would be accompanied by the selective use of South African economic and military arm-twisting. 1971 J. Wambaugh New Centurions xii. 209 When he got to the latticework he peered through and saw two young men, long sideburned twins with chain belts, *arm wrestling on a swaying table with a burning candle at each side of the table to scorch the back of the loser's hand. 1973 [see wrist-wrestling s.v. wrist 5d]. 1978 Globe & Mail (Toronto) 14 Aug. 5/1 The muscled gladiators who prevailed‥will represent Canada on Sept. 16 at Worlds of Fun Amusement Park in Kansas City, at the World Professional Armwrestling Association championships. 1986 P. Booth Palm Beach ii. 39, I remember the time when your ol' man and your granpappy set to arm wrestling on the bar. 1656 Heylin Two Journ. 42 Hands and *arme-wrists free from scabs.