Defn: Having three sepals, or calyx leaves.

TRISERIAL; TRISERIATE
Tri*se"ri*al, Tri*se"ri*ate, a Etym: [Pref. tri- + serial, seriate.]
(Bot.)

Defn: Arranged in three vertical or spiral rows.

TRISKELION; TRISKELE
Tris*kel"i*on, or Tris"kele, n. [Gr. three-legged. See Tri-;
Isosceles.]

Defn: A figure composed of three branches, usually curved, radiating from a center, as the figure composed of three human legs, with bent knees, which has long been used as a badge or symbol of Sicily and of the Isle of Man.

TRISMUS
Tris"mus, n. Etym: [NL., form Gr. (Med.)

Defn: The lockjaw.

TRISNITRATE
Tris*ni"trate, n. Etym: [Gr. nitrate.] (Chem.)

Defn: A nitrate formed from three molecules of nitric acid; also, less properly, applied to certain basic nitrates; as, trisnitrate of bismuth.

TRISOCTAHEDRON
Tris*oc`ta*he"dron, n. Etym: [Gr. octahedron.] (Crystallog.)