From the second edition (1989):
meta-, prefix
(ˈmɛtə) before a vowel normally met- (also before h, the resulting meth- being pronounced (mɛθ)),

repr. Gr. µετα-, µετ- (µεθ-), which occurs separately as the prep. µετά with, after; etymologically corresponding to mid prep. In Gr. the prefix is joined chiefly to verbs and verbal derivatives; the principal notions which it expresses are: sharing, action in common; pursuit or quest; and, especially, change (of place, order, condition, or nature), corresponding to L. trans-. In some few formations µετα- represents the prep. µετά in syntactical combination, with the sense after or behind, as in µετάϕρενον metaphrenon.
The words derived from Gr. words containing the prefix, or from assumed Greek types normally constructed, are given in their alphabetical place. The words enumerated in this article are modern formations, in which the prefix is employed in ways not strictly in accordance with Greek analogies. The prefix is often hyphened, and the a remains unelided before a vowel or h.

1. a. The supposed analogy of metaphysics (misapprehended as meaning ‘the science of that which transcends the physical’) has been followed in the practice of prefixing meta- to the name of a science, to form a designation for a higher science (actual or hypothetical) of the same nature but dealing with ulterior and more fundamental problems. metaˈchemistry ?nonce-wd., the chemistry of the supersensible. meta-ˈethics, a name applied to the study of the foundations of ethics, esp. of the nature of ethical statements; hence meta-ˈethical a. meta-ˈhistory, inquiry into the principles governing historical events; so meta-hiˈstoric(al adjs., transcending history, controlling the course of history. metaphiˈlosophy, inquiry into the problems ulterior to philosophy or philosophical theories; so metaphiloˈsophical a. metaphysiˈology, a name invented by G. H. Lewes for a doctrine of life and vital phenomena which should base itself on principles outside of and higher than those of physiology and the material organism; hence metaphysioˈlogical a., metaphysiˈologist. metasociˈology (see quot. 1970); so metasocioˈlogical, meta-socioloˈgistic adjs. meta-theˈology, (a) nonce-wd., a profounder theology than that recognized by divines; (b) the philosophical study of the nature of religious language or statements; hence meta-theoˈlogian, meta-theoˈlogical a. Similarly in meta-ˈelement, metaˈgnostic a., [cf. gnostic a.], metaorganism (see quots.); metapheˈnomenal a., existing behind phenomena. See also metageometry, metempiric.

1856 Emerson Eng. Traits, Lit. Wks. (Bohn) II. 106 It seems an affair of race, or of *metachemistry. 1888 W. Crookes in Jrnl. Chem. Soc. LIII. 487 The possible existence of bodies which, though neither compounds nor mixtures, are not elements in the strictest sense of the word;—bodies which I venture to call ‘*meta-elements’. 1949 A. J. Ayer Philos. Ess. (1954) x. 246 All moral theories‥are neutral as regards actual conduct. To speak technically, they belong to the field of *meta-ethics, not ethics proper. Ibid., Expounding my meta-ethical theory. 1957 D. M. Mackinnon Study in Ethical Theory i. 10 The moral philosopher is‥preoccupied with‥problems of meta-ethics, with the question of where ethical language belongs on the language-map. Ibid. 11 This problem of the relation of duty and good is in some sense meta-ethical. 1966 G. C. Kerner Revolution in Ethical Theory 1 The problems of ethical theory are thus‥problems‥of moral language;‥they are ‘meta-ethical’. Ibid. ii. 70 Meta-ethics is conceived to be a purely theoretical and ethically neutral enterprise. 1973 Nature 26 Jan. 249/2 With someone who prefers an incoherent picture of nature, I have no idea how to proceed—just as in meta-ethics, one is powerless to proceed with someone who regards a universe without sentience as possessing greater intrinsic value than one with sentience. 1886 H. Maudsley Nat. Causes & Supern. Seemings 122 Regions‥that are beyond knowledge, not beyond nature; *metagnostic, not metaphysical. 1929 R. Hughes tr. Deissmann's New Testament in Light of Mod. Res. vi. 172 The holy is pre-historic and *metahistoric. 1945 G. Dix Shape of Liturgy ix. 264 These *meta-historical facts of the resurrection and ascension. 1949 Mind LVIII. 411 The value of morals as ‘meta-historical reason’ controlling history and determining the future. 1969 P. A. Robinson Freudian Left 148 The typical practicing psychoanalyst carefully distinguished the discrete precepts and techniques of his therapeutic science from the ambitious meta-historical adventures in which Freud had indulged. 1957 Times Lit. Suppl. 27 Dec. 782/2 *Metahistory (which stands in much the same relation to history as metaphysics does to physics). 1964 C. S. Lewis Discarded Image viii. 175 What Virgil puts forward in a mythical form is precisely meta-history. 1866 Myers Phantasms of Living II. 278 That this body of ours‥is interpenetrated with a ‘*meta~organism’ of identical shape and structure, and capable sometimes of detaching itself from the solid flesh. 1844 H. P. Tappan Elem. Logic 12 Those objects which, by supposition, lie beyond immediate consciousness, are *metaphenomenal. 1882 G. S. Morris Kant's Critique vi. (1886) 189 No distinction of phenomena from the metaphenomenal, as objects of knowledge. 1942 Mind LI. 284 ‘Why are no philosophical disputes ever settled?’ It is with this ‘*metaphilosophical’ problem‥that Professor Ducasse's book‥is concerned. 1964 Philos. Rev. LXXIII. 554 Blakeley‥proposes an original and provocative metaphilosophical thesis. 1970 M. Lazerowitz in Metaphilosophy I. 91 *Metaphilosophy is the investigation of the nature of philosophy, with the central aim of arriving at a satisfactory explanation of the absence of uncontested philosophical claims and arguments. 1876 Lewes in Fortn. Rev. Apr. 479–86 *Metaphysiology. *Metaphysiological. *Metaphysiologists. 1959 R. Bierstedt in L. Gross Symposium Sociol. Theory 137 The distinction between methodological (or *metasociological) theory on the one hand and substantive (or sociological) theory on the other. 1964 P. Meadows in I. L. Horowitz New Sociol. 448 Formulations which phrase a *meta-sociologistic model, that is, the theme that beyond the teeming and changing varieties of social life and differentiated functions there are social patterns generating and guiding the social work life. 1958 W. Stark Sociol. of Knowl. i. iv. 197 A *metasociology which would be‥a study of man as he appears in all societies, of man as such. 1970 G. A. & A. G. Theodorson Mod. Dict. Sociol. 254 Metasociology, the branch of sociological theory that is concerned with the methods and logic of sociological inquiry, rather than with propositions, principles, and generalizations about social life. 1967 Philosophy XLII. 197 The *meta-theologian‥claimed that Christian discourse, as it stands, is incoherent. 1969 R. S. Heimbeck Theol. & Meaning i. 20 Since 1955, the quantity of *metatheological literature has multiplied many times over. a1615 Donne Ess. (1651) 129 A *Meta-theology and a Superdivinity above that which serves our particular consciences. 1957 I. M. Crombie in B. Mitchell Faith & Logic ii. 77 It is from reading theology, not meta-theology, that one can come to understand how theological statements work. 1959 P. Munz Probl. Relig. Knowl. 12 The meta-theology which I have put forward neither stands nor falls with any one particular theological opinion which I have expressed or implied. 1967 Philosophy XLII. 195 One piece of meta-theology which has won wide acceptance‥is that ‘God’ is not a substance-word.

b. Prefixed to various classificatory words to designate concern with the ulterior or underlying principles peculiar to that classification, as metacriterion, metacriticism, (hence metacritical adj., -ally adv.), metasystem, metatheorem, metatheory (so metatheoretic, -ical adjs.).

1953 C. E. Bazell Ling. Form v. 63 Universality of application is only one *meta-criterion for the choice of criteria. 1954 C. F. Hockett in Word X. 233 Neither any existing version of IA nor any existing version of IP meets all the metacriteria. 1963 Listener 3 Jan. 21/1 They [sc. the techniques of modern criticism] could make exciting sense (if not in strictly critical terms, then in *metacritical ones) of works which would have seemed absurd if taken literally. 1970 A. Rodway Truths of Fiction i. 9 Concentrate, metacritically, on what the text refers to.‥ Study of form is purely critical, of content either critical or metacritical; of what the work leads to, whether in the way of causes or effects or general topics, purely metacritical. 1966 Philosophy XLI. 320 The aesthetician‥is concerned (among other things) with *metacriticism. 1970 A. Rodway Truths of Fiction i. 6 The logical primacy of intrinsic criticism suggests that extrinsic criticism might also be called metacriticism. 1956 J. H. Woodger tr. Tarski's Logic, Semantics, Metamath. 116 It is possible to construct a particular science, namely the ‘*metasystem’, in which the given system is subjected to investigation. 1964 P. Meadows in I. L. Horowitz New Sociol. 452 Metasystem or general systems theory. 1969 New Scientist 4 Sept. 461/1 What Professor Beer is asking for is that we approach the problem at a higher level—the level of the ‘metasystem’. 1940 W. V. Quine Math. Logic ii. 89 We establish theorems wholesale, by arguments which show that the appropriate sequences could be found for each particular case. Such principles, describing general circumstances under which statements are theorems, will be called *metatheorems. 1943 Mind LII. 267 Closely connected with the distinction between use and mention is that between a theorem and a metatheorem, the latter being, as the name suggests, a theorem about theorems, wherein symbols are mentioned and names of symbols used. 1971 G. Hunter Metalogic p. xii, Complete proofs for metatheorems (theorems about a system) are‥more laborious for natural deduction systems than for axiomatic ones. Ibid. i. 11 A theorem about a theorem (also called a metatheorem) is a true statement about the system expressed in the metalanguage. 1965 B. Mates Elem. Logic viii. 128 We are now in a position to‥give informal proofs of a number of *metatheoretic generalizations about the theorems of logic. 1953 Mind LXII. 557 The *meta~theoretical problems of logical calculi, such as independence of axioms, completeness, and decision methods. 1956 E. H. Hutten Lang. Mod. Physics iii. 81 When we want to explain how scientific theories are constructed‥we must speak about them; and this requires a suitable terminology. This *meta-theory, or methodology, is as necessary to science as grammar is to ordinary language. 1963 Language XXXIX. 208 A metatheory for semantics must also exhibit the relations between semantics and other areas of linguistics. 1974 Sci. Amer. May 122/3 He outlines a metatheory in which the universe at every micromicroinstant branches into countless parallel worlds.

2. Path. Used to form adjs. applicable to diseases or symptoms, with the sense ‘arising subsequently to’ (that which is indicated in the body of the word). meta-arˈthritic, following or consequent on gout. metapneuˈmonic, following or consequent on pneumonia. metaˌsplenomeˈgalic [Gr. σπλήν spleen, µεγαλο-, µέγας great], preceded by enlargement of the spleen.

1898 Allbutt's Syst. Med. V. 862 The *meta-arthritic endocarditis. Ibid. 164 *Metapneumonic pleurisy. 1905 H. D. Rolleston Dis. Liver 308 *Metasplenomegalic hypertrophic biliary cirrhosis.

3. Anat. and Zool. Used to express the notion of ‘behind’ (cf. metaphrenon); also often that of ‘hinder’, ‘hindmost’, ‘situated at the back’; sometimes correlated with pro- and meso-. metaˈbranchial a. [Gr. βράγχια gills], applied to a division of the carapace of a crab situated behind and to one side of the mesobranchial lobe. metaˈfacial a., applied to the angle which the pterygoid processes make with the base of the cranium. ‖metapaˈrapteron Ent., the parapteron of the metathoracic segment; hence metapaˈrapteral a. (Cent. Dict.). metapneustic (-ˈpnjuːstɪk) a. Ent. [Gr. πνευστικ-ός relating to breathing], having a single pair of spiracles situated at the posterior end of the abdomen. metapore (ˈmɛtəpɔə(r)) [pore], an orifice in the pia mater covering the fourth ventricle of the brain; the foramen of Magendie. ‖metascuˈtellum, ‖metaˈscutum, the scutellum and scutum (respectively) of the metathorax of an insect; hence metascuˈtellar, metaˈscutal adjs. (in recent Dicts). metasthenic (-ˈsθɛnɪk) a. Ent. [Gr. σθένος strength], having most strength in the hinder part of the body; n. pl., a division of insects characterized in this way.

1877 *Metabranchial [see mesobranchial s.v. meso-]. 1878 Bartley tr. Topinard's Anthrop. ii. iii. 291 The *meta~facial angle of Serres, which the pterygoid processes form with the base of the skull. 1891 Bernard tr. Lang's Comp. Anat. i. 482 The tracheal system is then called *meta~pneustic. 1899 D. Sharp Insects ii. 450 (Camb. Nat. Hist.) Some begin life in the metapneustic state, and afterwards become amphipneustic. 1889 Buck's Handbk. Med. Sci. VIII. 123/2 The orifice here called *metapore. 1899 D. Sharp Insects ii. 313 (Camb. Nat. Hist.) The hind margin of the *metascutellum. 1863 Dana in Amer. Jrnl. Sci. Ser. ii. XXXVI. 323 The condition may be described as‥*Metasthenic‥if a posterior pair [of locomotive organs] is the more important and the anterior are weak or obsolete. Ibid. 335 The two highest divisions, Prosthenics and Metasthenics.

4. Bot. and Zool. Used with the sense ‘later’, ‘subsequent’, ‘more developed’; sometimes indicating the latest of three stages, correlated with proto- and meso-. ˈmetacneme [Gr. κνήµη tibia; cf. cnemial a.], a secondary mesentery which develops in some Zoantherians; so metacˈnemic a. metaneˈphridium [a. G. metanephridium (B. Hatschek Lehrbuch der Zoologie (1889) II. 162): see nephridium], in certain invertebrates, a nephridium with a ciliated opening into the coelom; so metaneˈphridial a. ˈmetaphase, [a. G. metaphase (E. Strasburger 1884, in Arch. f. mikrosk. Anat. XXIII. 260)], the stage in mitotic or meiotic nuclear division which follows prophase and precedes anaphase, during which the chromosomes become arranged with their centromeres on the equatorial plate; a dividing nucleus at this stage. metaˈphloem, a constituent of primary phloem which is formed after the earliest development of the shoot. ˈmetaphyte, ‖meˈtaphyton, a multicellular plant; hence metaˈphytic a. (Jackson Gloss. Bot. Terms 1900). metaˈtracheal a. arch., usu. in phrase metatracheal parenchyma, describing the structure of wood in which concentric bands of parenchyma independent of the vessels are formed. metaˈxylem, a constituent of the primary xylem which is formed after the earliest development of the shoot.

1900 J. E. Duerden in Johns Hopkins Univ. Circular XIX. 47/2 The first six pairs of mesenteries are found to differ so essentially in their mode of origin and significance from the mesenteries appearing later that I find it convenient to have some word which will include them either as a whole or individually. I therefore propose for them the term ‘Protocnemes’, and shall refer to the mesenteries subsequently developed as ‘*Metacnemes’. 1902 Ann. & Mag. Nat. Hist. IX. 397 The different fundamental types of metacnemic sequence now known within the Actiniaria and Madreporaria. Ibid., The metacnemes arise as unilateral pairs at one, three, seven, etc. regions within all the six primary exocoeles. 1940 L. H. Hyman Invertebrates I. vii. 589 In most forms [of sea anemone] additional septa called metacnemes arise in pairs. 1940 L. H. Hyman Invertebrates I. ii. 37 The nephridial system of the coelomate invertebrates is of the *metanephridial type, i.e., the nephridial tubules begin as coelomic openings. 1963 R. P. Dales Annelids v. 98 The metanephridial funnels or postnephridial solenocytes lie in the coelomic fluid. 1930 W. R. Coe in Biol. Bull. LVIII. 208 This type of excretory organ may be designated a *metanephridium in order to distinguish it from the more usual type, protonephridium, found in nemerteans. 1967 E. J. W. Barrington Invertebr. Struct. & Function xii. 236 The nephridium occurs in two main forms, the protonephridium and the metanephridium. 1890 Syd. Soc. Lex., *Metaphase,‥the stage of the nuclear spindle in karyokinesis. 1887 tr. Strasburger's Bot. 363 Now begin the phases of separation and rearrangement of the daughter-segments, the *metaphases of division. 1924 E. W. Macbride Study of Heredity ii. 42 The formation of the equatorial plate and of the spindle is known as the metaphase. 1961 Lancet 26 Aug. 489/1 Metaphases in freshly aspirated sternal and iliac crest marrow were analysed. 1962 Ibid. 26 May 1098/2 Rich crops of cells in metaphase were obtained twice. 1969 Times 20 June 7/3 Shortly before ovulation the oocyte goes through the process of cell division and then starts to divide a second time, a stage known as metaphase 2. 1973 Nature 1 June 290/2 Well-spread metaphases were photographed with a 95 × fluoride objective. 1902 Encycl. Brit. XXV. 413/1 In many cases external protophloem‥can be distinguished from *metaphloem. 1965 K. Esau Plant Anat. (ed. 2) xii. 292 The sieve elements of the metaphloem are commonly longer and wider than those of the protophloem. 1893 Shipley Zool. Invert. 3 The *Metaphyta and Metazoa, or the multicellular plants and animals. 1897 Hartog in Nat. Science Oct. 234 The higher animals and plants we term Metazoa and *Metaphytes respectively. 1908 Boodle & Fritsch tr. Solereder's Systematic Anat. Dicotyledons II. 1143 The wood parenchyma generally forms tangential bands (known as the ‘*metatracheal’ parenchyma in contrast to the ‘paratracheal’ parenchyma, aggregated round about the vessels). 1933 Tropical Woods XXXVI. 9 Metatracheal parenchyma, aggregated wood parenchyma forming concentric laminae, mostly independent of the vessels and vascular tracheids. 1970 Wilson & White Jane's Struct. Wood (ed. 2) vi. 116 Apotracheal parenchyma may occur as‥tangentially arranged sheets of cells‥or in more extensive tangential bands.‥ The two latter types are sometimes referred to as metatracheal parenchyma but this term is better avoided. 1902 Encycl. Brit. XXV. 415/1 Sometimes‥the centre of a bulky root stele has strands of *metaxylem‥scattered through it. 1965 K. Esau Plant Anat. (ed. 2) xi. 243 The metaxylem, which appears after the protoxylem, is in the process of differentiation while the shoot is elongating.

5. Geol. a. In imitation of metamorphism, the prefix has been used irregularly to form words referring to certain specific varieties of metamorphic processes, as metaˈchemic a., metaˈpepsis (hence metaˈpeptic a.), metaˈtaxis (hence metaˈtaxic a.), meˈtatropy: see quots.

1893 Geikie Text-bk. Geol. iv. viii. 596 note, Metasomatosis, metasomatic‥and *metachemic applied to chemical metamorphism or alteration of constitution or substance. 1878 Kinahan Geol. Irel. 175 One kind of Metamorphism is Regional, or extends over large areas. The rocks affected by it seem to have been under the influence of intensely heated water or steam, which, as it were, stewed them, from which the action may be called *metapepsis. Ibid. 177 *Metapeptic rocks. Ibid., Metapeptic action. 1889 A. Irving Metamorph. Rocks 65 *Metataxic work done by Solar and Lunar Tides. Ibid. 5 Slaty cleavage and its concomitant phenomena‥will be considered under the term *Metataxis. Footn. This term is preferred to the cognate term Metastasis (Bonney). Ibid., *Metatropy, or changes in the physical characters of rock-masses.

b. Prefixed to the names of rocks or of classes of rock to indicate that they have undergone metamorphism, as metadiorite, metadolerite, metagranite, metasediment (hence metasedimentary adj.), metasyenite, metavolcanic; also metaigneous adj.

1876 J. D. Dana in Amer. Jrnl. Sci. & Arts XI. 121 The rocks are‥Metamorphic doleryte, metamorphic diabase, and metamorphic melaphyre.‥ To distinguish these metamorphic rocks from the igneous of the same composition, they are named, on my suggestion, metadoleryte, metadiabase, and metamelaphyre. The examples are part of a long series of rock species which have representatives both among igneous (or intrusive) and metamorphic rocks. Other kinds are dioryte and metadioryte, syenyte and metasyenyte, felsyte and metafelsyte, etc. 1920 A. Holmes Nomencl. Petrol. 154 Meta-, a prefix used before the names of igneous rocks to signify that the mineral and chemical composition of the latter have been modified by alteration. 1942 M. P. Billings Struct. Geol. xii. 215 Metasediments, metavolcanics, and meta-igneous rocks are metamorphic rocks derived, respectively, from sedimentary, volcanic, and igneous rocks. 1961 J. Challinor Dict. Geol. 126/1 Meta-(rock). A metamorphosed rock which was originally of the kind or type included in the name. Thus ‘metasediment’ or ‘metasedimentary rock’, ‘meta-igneous rock’, ‘metadolerite’, &c. 1973 Nature 21 Sept. 120/1 The metasediments occur in a (refolded) syncline among granitic gneisses. Ibid. 139/2 The lithology of some of these enclaves strongly suggests that they were originally supracrustal rocks similar to those that occur at Isua, including metasedimentary ironstones.

6. In Chemistry. a. Meta- is used to designate compounds derived from, metameric with, or resembling in composition those to the names of which it is prefixed, as metachloral, metaldehyde, etc. More systematically, it is used to distinguish one class of acids and their corresponding salts from another class (the ortho- acids) consisting of the same elements in different proportions, the meta- acids containing one, two, or three molecules of water less than the ortho- acids; the salts of these acids have names formed by replacing -ic by -ate. (A few of these compounds will be found in their alphabetical place; the most important of those remaining are placed below.)
The use of the prefix in chemistry was first introduced by Graham in 1833 (Phil. Trans. 253): see metaphosphate, metaphosphoric. The more definite use (correlated with ortho-) was introduced by Odling in 1859.

1861 Odling Man. Chem. i. xiii. Contents, Phosphorus and Oxygen.‥ Meta-compounds. 1892 Morley & Muir Watts' Dict. Chem., Meta-acids and meta-salts.

metaˈboric acid, ‘a white powder, obtained by heating ordinary boric acid or orthoboric acid to 100° C.’ (Syd. Soc. Lex. 1890). metaˈcellulose, the substance of which the cell-walls of fungi consist, differing from ordinary cellulose. metaˈchloral, a white amorphous solid formed by the action of sulphuric acid on chloral. metaˈcresol, one of the three modifications of cresol (ortho-, meta- and paracresol). metaˈgelatin, a form of gelatin that remains fluid, used in photography, made by boiling and cooling a solution of gelatin several times. metaˈgummic = metarabic. metaˈlumina, a name given to the soluble dihydrate of aluminium obtained by the action of heat on a solution of the acetate. metaˈmorphia, metaˈmorphine: see quots. meˈtamylene, ‘a compound polymeric with amylene, contained in the higher portion of the distillate produced by heating amylic alcohol with sulphuric acid’ (Watts). meta-oˈleic (also metoˈleic) acid, an acid resulting from the action of sulphuric acid on oleic acid. metaoxybenˈzoic acid, ‘an isomeride of salicylic acid’ (Syd. Soc. Lex.). metaˈpectic acid, the final product of chemical action upon pectin. metaˈpectin, an isomeric form of pectin produced by boiling with dilute acids. metaˈprotein, an intermediate product in the hydrolysis of a protein which is soluble in acids and alkalis but insoluble in water. meˈtarabic acid, ‘a substance, also called Cerasin, obtained by heating gum arabic to 100° C.’ (Syd. Soc. Lex.). meˈtarsenic acid: see quot. metasiˈlicic acid, a transparent vitreous substance obtained by drying silicic acid over anhydrous sulphuric acid. metatarˈtaric acid, a modification of tartaric acid obtained by melting it. metatiˈtanic acid: see quot. metaˈtoluic acid: see quot. metaˈtungstic acid, a yellow solid used as a test for alkaloids.

1863 Watts Dict. Chem. I. 639 Nearly all borates may be arranged in two classes, orthoborates and *metaborates (so called from their analogy with the ortho- and metaphosphates and silicates). 1885 G. L. Goodale Physiol. Bot. (1892) 35 note, Cellulose dissolves at once in cuprammonia; paracellulose, only after the action of acids; *metacellulose, not even then. 1876 Encycl. Brit. V. 676/2 When kept for some days‥chloral undergoes spontaneous change into the polymeride *metachloral,‥a white porcelaneous body. 1881 Watts Dict. Chem. VIII. 1286 *Metacresol. 1858 Sutton Dict. Photogr., *Metagelatine. 1879 Encycl. Brit. X. 131/2 Gelatin so treated [with hot solutions of oxalic acid] has been called metagelatin. 1862 Watts tr. Gmelin's Handbk. Chem. XV. 205 *Metagummic Acid. Ibid. 206 *Metagumate of lime. 1862 Graham in Jrnl. Chem. Soc. XV. 247 Two soluble modifications of alumina appear to exist, alumina and *metalumina. 1890 Syd. Soc. Lex., *Metamorphia, one of the alkaloids separated from laudanum. 1865 Watts Dict. Chem. III. 976 *Metamorphine, an opium-base, the hydrochlorate of which is obtained, as a residue, in the preparation of opium-tincture by means of lime and sal-ammoniac. 1838 T. Thomson Chem. Org. Bodies 124 M. Fremy was unable to obtain any of the *meta-oleates in a crystallized state. Ibid. 123 *Meta-oleic acid differs from it [sc. oleic acid] by containing two additional atoms of water. 1873 C. H. Ralfe Phys. Chem. 132 The parapeptone being removed by filtration, the neutralized filtrate is again acidified when another precipitate, *metapeptone, is thrown down. 1909 Cent. Dict. Suppl., *Metaprotein. 1911 Encycl. Brit. XIX. 922/1 The first result of the action of this secretion on protein matter is to render it soluble—a metaprotein or acid albumin (syntonin) being formed. 1949 G. B. Bachman Org. Chem. xviii. 220 Primary derivatives: proteins, metaproteins, and coagulated proteins. 1861 Odling Man. Chem. i. 338 *Metarsenates and pararsenates are converted respectively into monometallic and dimetallic common arsenates by the action of water. Ibid., *Metarsenic acid HAsO3, is formed by gradually heating common arsenic acid to a temperature of 200°–205°. 1859 *Meta-silicates [see ortho- 2]. 1872 Watts Dict. Chem. VI. 825 *Metasilicic Acid. 1848 Brande Chem. (ed. 6) 1315 Saccharic Acid.‥ Erdmann, who repeated Guérin Varry's experiments in 1837, regarded this acid as isomeric with tartaric acid, and called it *metartaric acid. 1856 Watts tr. Gmelin's Handbk. Chem. X. 328 *Metatartrate. 1854 R. D. Thomson Cycl. Chem., *Metatitanic Acid, Ti3O6. Small shining plates, separating when anhydrous bichloride of titanium is saturated with carbonate of barytes, adding water and boiling rapidly. 1873 Jrnl. Chem. Soc. XI. 276 Uvitic acid prepared by Finckh's process from pyrotartaric acid decomposes into *metatoluic acid when heated with lime. 1854 R. D. Thomson Cycl. Chem., *Metatungstic Acid.

b. In the names of isomeric benzene di-derivatives, meta- denotes those compounds in which the two radicals that replace hydrogen in the benzene-ring are regarded as attached to alternate carbon atoms. (The use was introduced by Körner in 1867; cf. ortho- 2b, para- 2b.) So also metacoumaric acid, metacoumarate.
As the number of these is unlimited, no list is given; a few examples are appended in the quots. below.

1873 Jrnl. Chem. Soc. XI. 1147 The metadiamidobenzene of Griess. 1875 Ibid. XIII. 156 When metachlorophenol is fused with potash, it is readily converted into pyrocatechin; the relation between metanitrophenol, metachlorophenol, and pyrocatechin being thus proved. Ibid., Metanitrometachlorophenol appears to be converted into metanitrodichlorophenol by the action of chlorine. 1876 H. E. Armstrong ibid. I. 212 The three Isomeric Dibromobenzenes.‥ Paranitrobromobenzene,‥Metanitrobromobenzene,‥Orthonitrobromobenzene. 1879 Watts Dict. Chem. VIII. 210, α- or metapherylene-diamine. 1899 J. Cagney Jaksch's Clin. Diagn. vii. (ed. 4) 381 Metadiamido-benzol is coloured a deep yellow by nitrites. 1905 Brit. Med. Jrnl. 27 May 1144 They [i.e. benzenoid ortho- and para- compounds] both differ markedly from their isomerides of the meta-series.‥ In the meta-compound these groups [i.e. ortho-coumaric and para-coumaric acids] are in apothetic positions with respect to each other so that the meta-acid might be expected to exhibit the dual properties of a phenol and a cinnamic acid. Ibid., Sodium meta-coumarate.‥ The meta-coumaric acid required for this preparation was produced synthetically from meta-nitrobenzaldehyde.

7. Min. Used to designate a mineral that is found along with another or is closely related to it, spec. denoting (partial) dehydration; as metabrushite (a calcium phosphate allied to brushite), metachlorite, metacinnabar(ite, metagadolinite, metalonchidite, metanocerite, metasericite, metastibnite, metavoltine (see A. H. Chester Dict. Min. 1896).

1854 Dana Syst. Min. (ed. 4) II. 297. 1865 Julien in Amer. Jrnl. Sci. Ser. ii. XL. 371 Metabrushite. This new mineral has been observed to occur only with the guano as a matrix.