trimester trimester /traɪˈmɛstɝ/

noun

1. One of three divisions of an academic year  ( trimester )
   one of three divisions of an academic year
   
2. A period of three months; especially one of the three three-month periods into which human pregnancy is divided  ( trimester )
   a period of three months; especially one of the three three-month periods into which human pregnancy is divided
    She is in her second trimester and feeling much better than in her first
   She is in her second trimester and feeling much better than in her first