1.American EnglishAmESE one of three periods of equallength that the school year is divided into 〔一学年三学期中的〕一学期SYN British English term
2.MBone of the three-month periods of pregnancy 〔妊娠三期中的〕一期
Examples from the Corpus
trimester• Abortions after the first trimester cost considerably more than those within the first twelve weeks.• Coelocentesis may be suitable for prenataldiagnosis in the first trimester.• She may even concede that hospitalisation is best, at least for the last trimester.• Preeclampsia is a potentially fatalcondition that usually strikes in the last trimester of pregnancy.• Somehow, even the dumbest pregnancy cliches seem appealing in your second trimester.• They also observed a maternal hypoglycaemic response in their subjects in the thirdtrimester.• As pregnancy progresses, the placentasecretes more progesterone which peaksmidway into the third trimester and then levels off.• Athletes who have trained normally through the first two trimesters have deliverednormalbabies. 4.
Origintrimester
(1800-1900)Frenchtrimestre, from Latintrimestris, from tri-“three” + mensis“month”