1. (noun) a period of three months; especially one of the three three-month periods into which human pregnancy is divided

• period
• period of time
• time period

2. (noun) one of three divisions of an academic year

• academic session
• academic term
• school term
• session

1. (noun) a period of three months; especially one of the three three-month periods into which human pregnancy is divided

• first trimester
• second trimester
• third trimester