trigono-
(ˈtrɪgənəʊ, trɪˈgəʊnəʊ)
combining form repr. Gr. τρίγωνο-ς adj. three-cornered, triangular, neut. τρίγωνον as n. a triangle; used in several scientific terms. trigonoˈcephale, -ˈcephalous adjs., Zool. [Gr. κεϕαλή head], having a triangular head, as a serpent of the genus Trigonocephalus; so trigonoceˈphalic a. Anthrop., having a malformation of the skull, caused by premature closing of the medio-frontal suture, in which the sides are flat and converge to an apex in front; trigonoˈcephaly, the condition of being trigonocephalic. trigonocerous (-ˈɒsərəs) a. Zool. [Gr. κέρας horn], having horns of triangular section. trigonoˈcuneate a. [L. cune-us wedge], triangularly wedge-shaped. triˈgonodont a. Comp. Anat. [Gr. ὀδούς, ὀδοντ- tooth], having the primitive cusps of the molar teeth arranged in a triangle. triˈgonotype Geom. [Gr. τύπος figure, image, type], name for a trigonal trapezohedron (Cent. Dict. 1891).
| 1865 Morn. Star 13 Mar., A *trigonocephale black serpent, brought over in 1842, is alive. |
| 1878 Bartley tr. Topinard's Anthrop. v. 176 *Trigonocephalic, skull triangular at the top anteriorly, supposed to be owing to the medio-frontal synostosis. |
| Ibid. Index, *Trigonocephaly. 1904 Duckworth Morphol. & Anthropol. x. 253 A skull which viewed from above presents a peaked or rostrated appearance and has been described as triangular or trigonocephalic. |
| 1848 Smart, *Trigonocerous, having three-angled horns,—applied to a species of fossil stag. 1864 in Webster. |
| 1822 J. Parkinson Outl. Oryctol. 224 *Trigono-cuneate, rather smooth on the upper part, longitudinally sulcated. |
| 1897 H. F. Osborn in Amer. Nat. Dec. 1002 ‘*Trigonodont’ is most appropriate because the first step in molar morphology is to identify the primitive triangle. |