traˈpezian, a. Cryst.
[f. as prec. + -an. Cf. mod.F. trapézien (Littré).]
Having trapeziform lateral faces in two rows between the two bases, as a crystal of barium sulphate.
| 1757 tr. Henckel's Pyritol. 23 Prismatical, trapezian, or irregular. 1805–17 R. Jameson Char. Min. 203 A crystal is said to be..Trapezian, when its lateral surfaces consist of trapezia, which lie in two rows, between two bases, as in trapezian heavy-spar... It is a rectangular four-sided table, bevelled on the extremities, where the bevelling planes are trapeziums. 1828 in Webster. Hence in later Dicts. |