TRIGONAL
Trig"o*nal, a.

Defn: Having three angles, or corners; triangular; as, a trigonal stem, one having tree prominent longitudinal angles.

TRIGONE
Tri`gone", n. Etym: [F., literally, a trigon.] (Anat.)

Defn: A smooth triangular area on the inner surface of the bladder, limited by the apertures of the ureters and urethra.

TRIGONIA Tri*go"ni*a, n. Etym: [NL. See Trigon. So called in allusion to the triangular shape of some species.] (Zoöl.)

Defn: 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.

TRIGONOCEROUS
Trig`o*noc"er*ous, a. Etym: [Gr. (Zoöl.)

Defn: Having horns with three angles, like those of some species of goats.

TRIGONODONT
Trig"o*no*dont`, a. [See Trigon; Odonto.]

Defn: See Trituberculy.