9 letters · 11 points in Scrabble
noun a period of three months; especially one of the three three-month periods into which human pregnancy is divided
noun one of three divisions of an academic year
originPIE word *tréyes From French trimestre, from Latin trimestris (“of three months”), from trēs (“three”) + mensis (“month”).
Etymology from Wiktionary, CC BY-SA 3.0