tri·mes·ter
noun/traɪˈmestə(r)/
/traɪˈmestər/
- (medical) a period of three months during the time when a woman is pregnant
妊娠期（以三个月为单位） - the first trimester of pregnancy
妊娠的头三个月
- the first trimester of pregnancy
- (North American English) (also term especially in British English)one of the three periods in the year during which classes are held in schools, universities, etc.
学期（学校一年分三个学期） - The school year is divided into three trimesters.
一学年分三个学期。
- The school year is divided into three trimesters.
Word Originearly 19th cent.: from French trimestre, from Latin trimestris, from tri- ‘three’ + mensis ‘month’.