[f. Gr. τρι-, TRI- + γράμμα, -ατ-, line, letter, or γραμμή stroke, line.] a. An inscription of three letters; also, = TRIGRAPH (Webster, 1864). b. A figure or character formed of three strokes. c. Geom., etc. A set of three lines; spec. the figure formed by three straight lines in one plane not intersecting in the same point; also more generally, any figure composed of three elements.
1606. Birnie, Kirk-Buriall (1833), 17. Inscryving their tombes with a trigram of D.M.S.
1802. J. Hager, Babylon, Inscr., 54. What connexion is there between the first trigram, or three united strokes, to represent heaven, and … the second trigram,… three broken ones, to represent the earth?
1882. Athenæum, 2 Sept., 297/1. The hexagrams … are composed each of a double trigram…. The trigrams consist of three lines one above the other.
1897–8. Ann. Rep. Bur. Amer. Ethnol., 842. The swastika itself merely represents two superposed trigrams.
So Trigrammatic, Trigrammic adjs., consisting of three letters (= TRILITERAL) or sets of letters; Trigrammatism = TRILITERALISM.
1834. Encycl. Brit. (ed. 7), VIII. 560/1. The trilingual, or rather trigrammatic stone of Rosetta.
1839. Donaldson, New Cratylus, § 70 (1850), 107. Their apparent [Semitic] trigrammatism, their etymological disintegration, and the tertiary condition in which their oldest remains are found, must be referred to the constant intermixtures, re-unions [etc.].
1846. Worcester, Trigrammic, containing three letters. Thomson.
1847. Webster, Trigrammatic, containing three sets of characters or letters. Gliddon.
