a. Obs. rare. [f. L. trimenstris, erron. form of trimestris: see TRIMESTER.] Ripening in three months.
c. 1440. Pallad. on Husb., I. 260. Trymenstre seed in heruest forto sowe In londis cold is best.
So Trimenstruous, Trimensual adjs. (rare-–0) [f. TRI- + MENSTRUOUS, etc.]: see quots.
1656. Blount, Glossogr., Trimestruous, of three moneths age.
1658. in Phillips.
1891. Cent. Dict., Trimensual, happening every three months.
