Triangle, trī′ang-gl, n. (math.) a plane figure with three angles and three sides: a musical instrument of percussion, formed of a steel rod bent in triangle-form, open at one angle: a frame of three halberds stuck in the ground to which soldiers were formerly bound to be flogged (generally pl.).—adjs. Trī′angled, Triang′ūlar, having three angles.—n. Triangūlar′ity.—adv. Triang′ūlarly.—v.t. Triang′ūlāte, to survey by means of a series of triangles.—adv. Triang′ūlātely.—n. Triangūlā′tion, act of triangulating: the series of triangles so used.—adj. Triang′ūloid. [Fr.,—L. triangulum—tres, three, angulus, an angle.]
Triapsal, trī-ap′sal, adj. having three apses.—Also Triap′sidal.
Triarchy, trī′ar-ki, n. government by three persons: a state governed by three persons. [Gr. triarchia—treis, tria, three, archē, beginning, sovereignty.]
Triarian, trī-ā′ri-an, adj. of the third rank.
Trias, trī′as, n. (geol.) the oldest group of the Mesozoic or Secondary strata, formerly associated with the Permian rocks under the name of the New Red Sandstone.—adj. Trias′sic. [So called by the German geologists, from their threefold grouping of the system, from Gr. trias, union of three.]
Triatomic, trī-a-tom′ik, adj. consisting of three atoms: trivalent.
Triaxial, trī-ak′si-al, adj. having three axes.—n. Triax′on. [L. tres, tri-, three, axis, axis.]
Tribasic, trī-bā′sik, adj. having three hydrogen atoms replaceable by equivalents of a base—of some acids.
Tribble, trib′l, n. a horizontal frame for drying paper, having wires stretched across it.