[a. late L. trias, a. Gr. τριάς the number three: see TRIAD. In 2, a. Ger. Trias.]
1. The number three; a set of three, a triad.
1610. Bolton, Elem. Armories, 182. One is onely best: next to that the Trias, Ternio, or number three, and so the rest of the Odde to Fifteen.
1635. Heywood, Hierarch., II. 68. Sometimes, what’s proper vnto Man alone, Is giuen to this Trias, three in One: As, when we attribute vnto him Wings.
1728. H. Herbert, trans. Fleury’s Eccl. Hist., I. 250. This is the first time that we meet in the ancients with the word Trias, or Trinity in this sense.
1864. Daily Tel., 9 Sept. A people with whom drinking, smoking, and spitting are the Trias of social bliss.
2. Geol. Name for the series of strata lying immediately beneath the Jurassic and above the Permian; so called because divisible, where typically developed (as in Germany), into three groups (Keuper, Muschelkalk, and Bunter Sandstein); represented in Britain by the Upper New Red Sandstone and associated formations.
1841. Murchison, etc., in Proc. Geol. Soc. Lond. (1842), III. 403. The Trias of German geologists.
1842. Sedgwick, in Hudson’s Guide Lakes (1843), 204. In France and Germany the series of rocks … admits of a triple division (called ‘Trias,’ or the ‘Triassic system’).
1876. Page, Adv. Text-bk. Geol., xvi. 289. The reason for regarding the Trias as mesozoic.
1912. Return Brit. Museum, 169. A slab of Rhynchocephalian and other footprints from the Trias of Storeton, Cheshire.
attrib. and Comb. 1855. J. Phillips, Man. Geol., 248. Bands of red and blue trias-like sandstones and clays.
1867. W. W. Smyth, Coal & Coal-mining, 240. Reaching coal beneath the Permian and Trias formations.
