a. [f. mod.L. trimer-us (ad. Gr. τριμερής, f. τρι-, TRI- + μέρος part) + -OUS.] Having, consisting of, or characterized by three parts: spec. a. Bot. Having the parts of the flower, or the leaves, in series or whorls of three. b. Entom. Consisting of three segments or joints, as the tarsi in certain insects (see trimeran below); of an insect, having such tarsi (= trimeran).
1826. Kirby & Sp., Entomol., III. xxxv. 685. Trimerous insects are those whose tarsi consist of only three joints. Ibid., IV. xlvii. 378. Tarsi mostly trimerous, rarely dimerous.
1845. Lindley, Sch. Bot., viii. (1858), 129, note. Trimerous means that they [parts of a flower] are a power of 3.
1857. Henfrey, Bot., 226. Schizandraceæ … calyx and corolla 3-merous.
1869. Student II. 12. Polymerous leaves may be dimerous, trimerous, etc. according to their number of meriphylls.
1875. Bennett & Dyer, trans. Sachs’ Bot., 570. Among the dimerous and trimerous flowers of the orders Polycarpæ and Cruciflor‘.
So Trimeran Entom., adj. belonging to the division Trimera of beetles, or of hymenopterous insects, characterized by trimerous tarsi; sb. an insect of either of these divisions; Trimere Zool., a division of the third order in the supporting reticular skeleton of extinct siliceous sponges; Trimerite Min., a rare silicate of glucinum, manganese, and calcium, occurring in pinkish pseudo-hexagonal crystals, shown by their optical properties to be combinations of three triclinic individuals (Cent. Dict., 1891).
1842. Brande, Dict. Sci., etc., *Trimerans, Trimera,… the name of a section of Coleopterous insects, including those which have each tarsus composed of three articulations.
1909. Cent. Dict. Suppl., *Trimere.
1896. Chester, Dict. Names Min., 274. *Trimerite, Silicate of glucinum, manganese, and calcium, found in brilliant pinkish crystals.
