noun ·Moderate ·College level

Definitions

Noun

1. 1
   A period of three months or about three months; (financial): quarter.

   "She is in the second trimester of her first pregnancy."

2. 2
   one of three divisions of an academic year wordnet
3. 3
   One of the terms of an academic year in those learning institutions that divide their teaching in three roughly equal terms, each about three months long. Compare semester.

   "The school operates on a trimester schedule."

4. 4
   a period of three months; especially one of the three three-month periods into which human pregnancy is divided wordnet

Synonyms

All synonyms

quarterabundant yearacademic yearannumbissextile yearcalendar month

Example

More examples

"She is in the third trimester of her pregnancy."

Etymology

PIE word *tréyes From French trimestre, from Latin trimestris (“of three months”), from trēs (“three”) + mensis (“month”).

Related phrases

fourth trimester

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.