Defn: One of the Trimera. Also used adjectively.

TRIMEROUS
Tri"mer*ous, a. Etym: [See Trimera.] (Bot.)

Defn: Having the parts in threes.

TRIMESITIC
Tri`me*sit"ic, a. Etym: [Pref. tri- + mesitylene + -ic.] (Chem.)

Defn: Of, pertaining to, or designating, a tribasic acid, C6H3.(CO2)3, of the aromatic series, obtained, by the oxidation of mesitylene, as a white crystalline substance. [Written also trimesic.]

TRIMESTER Tri*mes"ter, n. Etym: [L. trimestris of three months; tri- (see Tri-) + mensis month: cf. F. trimestre.]

Defn: A term or period of three months.

TRIMESTRAL
Tri*mes"tral, a.

Defn: Trimestrial. Southey.

TRIMESTRIAL
Tri*mes"tri*al, a.