2. (Astrol.) (a) A division consisting of three signs. (b) Trine, an
aspect of two planets distant 120 degrees from each other. Hutton.
3. (Gr. & Rom. Antiq.) (a) A kind of triangular lyre or harp. (b) A
kind of game at ball played by three persons standing at the angular
points of a triangle.
Trig"o*nal (?), a. Having three angles, or corners; triangular; as, a
trigonal stem, one having tree prominent longitudinal angles.
<! p. 1539 !>
||Tri`gone" (?), n. [F., literally, a trigon.] (Anat.) A smooth
||triangular area on the inner surface of the bladder, limited by the
||apertures of the ureters and urethra.
||
||Tri*go"ni*a (?), n. [NL. See Trigon. So called in allusion to the
||triangular shape of some species.] (Zoöl.) A genus of pearly bivalve
||shells, numerous extinct species of which are characteristic of the
||Mesozoic rocks. A few living species exist on the coast of Australia.
||
Trig`o*noc"er*ous (?), a. [Gr. &?; triangle + &?; horn.] (Zoöl.) Having
horns with three angles, like those of some species of goats.
{ Trig`o*no*met"ric (?), Trig`o*no*met"ric*al (?), }[Cf. F.
trigonométrique.] Of or pertaining to trigonometry; performed by the
rules of trigonometry.
—Trig`o*no*met"ric*al*ly, adv.
Trigonometrical curve, a curve one of whose coördinates is a
trigonometric function of the other. — Trigonometrical function. See
under Function. — Trigonometrical lines, lines which are employed in
solving the different cases of plane and spherical trigonometry, as
sines, tangents, secants, and the like. These lines, or the lengths of
them, are trigonometrical functions of the arcs and angles to which
they belong. — Trigonometrical survey. See under Survey.
Trig`o*nom"e*try (?), n.; pl. -tries (#). [Gr. &?; a triangle + -metry:
cf. F. trigonométrie. See Trigon.] 1. That branch of mathematics which
treats of the relations of the sides and angles of triangles, which the
methods of deducing from certain given parts other required parts, and
also of the general relations which exist between the trigonometrical
functions of arcs or angles.