[ad. med.L. triangulāt-us triangular (Albertus Magnus, a. 1255), f. L. triangul-um TRIANGLE: see -ATE2; but possibly pa. pple. of med.L. *triangulāre vb.]
1. Having three angles, triangular; in later use only in Nat. Hist., applied to parts or structures of triangular form.
1611. Hopton, Speculum Topogr., II. ii. 187. Be it round, square, triangulate, or multiangulate.
1819. G. Samouelle, Entomol. Compend., 166. Antennæ with the three last joints forming an oblong triangulate mass.
1852. Dana, Crust., I. 307. A few species have a somewhat triangulate and subrostrate form.
2. Made up or composed of triangles. (In later use in Nat. Hist.) † Also as sb. a figure made up of triangles (obs.)
1610. Hopton, Baculum Geodæt., VI. xiv. 135. The sides of a tryangulate are more by 2, then the tryangles whereof he is made. Ibid. (1611), Speculum Topogr., I. ii. 7. Of Triangulates. A Triangulate is a mixt figure composed of Triangles, and may be resolued into the same againe.
1766. Compl. Farmer, s.v. Surveying, Right-lined figures … are either triangles or triangulate, that is, such as are compounded of, and resolvable into triangles.
3. Nat. Hist. Marked with triangles; having triangular markings.
1891. Cent. Dict., s.v., A triangulate bar is generally formed of triangles with their bases together…; it is a form of ornamentation common on the wings of Lepidoptera.
Hence Triangulately adv., in a triangulate manner; triangularly; so as to form triangles.
1852. Dana, Crust., I. 428. Carpus triangulately dilated at inner margin.
1891. Cent. Dict., s.v., A margin or surface marked triangulately with black.
