the L. adv. ter ‘thrice,’ in comb.
1. Prefixed to adjs., in sense ‘thrice, three times,’ as ter-trinal, consisting of three sets of three; also expressing a high degree, as ter-sacred [L. ter sacer], thrice sacred.
1600. W. Watson, Decacordon (1602), Pref. A vj b. The tersacred Apostolicall Romane Church. Ibid., 7. Directing his hand to that tender tersacred and euer blessed heart.
1876. Douse, Grimm’s L., § 25. 53. It is certain that the symmetrical ter-trinal trinity constituted by all these three systems together cannot have existed from all time.
b. Prefixed to adjs. and sbs.: expressing three-fold recurrence or continuance; as ter-diurnal a., occurring or done thrice a day; ter-millenary [after tercentenary], a three-thousandth anniversary.
1892. Ld. Kelvin, Presid. Addr. R. Soc., 30 Nov. The largeness of the solar semi-diurnal, ter-diurnal, and quarter-diurnal constituents found by the harmonic analysis.
1864. Realm, 15 June, 6. The festivities held there by so many millions of our dusky fellow-subjects in honour of the termillenary of that sweet swan of Nerbudda.
c. See also TERCENTENARY, TERGEMINATE, etc.
2. Chem. With the names of classes of compounds, as acetate, bromide, chloride, chromate, fluoride, iodate, nitrate, oxide, sulphate, tannate, etc., expressing the presence of three atoms, molecules, or combining equivalents of the element or radical indicated by the rest of the word, as nitrogen terchloride, NCl3, potassium terchromate, K2O . 3CrO2, or K2Cr3O10, ternitrate of bismuth, Bi(NO3)3, etc. Now mostly superseded by TRI-.
1836. Brande, Chem. (ed. 4), 773. Terchloride of Chromium. (Chr+O3C.)
1838. T. Thomson, Chem. Org. Bodies, 258. It is … a tertannate.
1849. D. Campbell, Inorg. Chem., 111. Besides this iodate of potash, there are other two, namely, a biniodate and a teriodate.
1853. W. Gregory, Inorg. Chem. (ed. 3), 240. Antimony…. This valuable metal is chiefly found in the mineral called antimony, which is a tersulphuret, SbS3.
1853. Ure, Dict. Arts, I. 1058. The explosive compound, the teriodide of nitrogen.
1856. Miller, Elem. Chem., II. 914. Terfluoride of chromium forms deep red fumes of chromic acid.
1869. Roscoe, Elem. Chem., 230. A third salt, termed ter-chromate [ed. 1882 trichromate], K2Cr3O10, crystallizes out.
1883. Hardwich’s Photogr. Chem. (ed. Taylor), 55. There are two Chlorides of Gold—viz., the Protochloride and the Terchloride. The latter is the one used in Photography.
b. In other compounds, as † ter-atomic a., of three atoms, TRIATOMIC; ter-equivalent, -valent a. = TRIVALENT; ter-valence = TRIVALENCE.
1860. Frankland, in Q. Jrnl. Chem. Soc., XIII. 192. Organo-metallic compounds … are uniatomic, biatomic, teratomic, or quadratomic, according to the number of molecules requisite to complete their saturation.
1866. Macadam, G. Wilson’s Inorg. Chem., § 1109. The Triatomic, Trihydric, or Terequivalent (Terivalent) elements.
1869. Eng. Mech., 12 Nov., 198/3. The elements are classified as triatomic or tervalent, with three attractions, as nitrogen.
1903. Athenæum, 3 Jan., 22/2. We wish that the translator had avoided the use of such hybrid words as monovalent, divalent, trivalent, tetravalent, and pentavalent when he had to hand the equally expressive and less mongrel words univalent, bivalent, tervalent, quadrivalent and quinquevalent.
