Trimester

How to spell trimester

9 letters · 3 syllables

How to pronounce trimester

Say the part in capitals loudest.

What does trimester mean?

1. nounAny of three roughly equal periods, especially one of the three stages of a human pregnancy.
2. nounOne of three terms into which some schools and colleges divide the academic year.

Trimester in a sentence

• Morning sickness often eases after the first trimester.

• The college splits the year into a fall, winter, and spring trimester.

• The midwife scheduled a scan for the second trimester.

• Final grades were posted at the end of each trimester.

Where does trimester come from?

Language of origin: Latin

The word goes back to the Latin trimestris, an adjective meaning 'of three months' or 'lasting three months', which was built from tri- 'three' and mensis 'month'. Latin speakers used it for anything that ran in a three-month cycle, including crops sown to ripen over a single season. It passed into French as trimestre, a recurring quarter of the year, and English borrowed it in the early 1800s, keeping the Latin -ester spelling rather than the French ending. The mensis root is the same one that sits inside 'menstrual' and even 'month' itself, all tracing back to the moon and its monthly cycle. That hidden 'mester' (not 'mister' or 'minister') is the spelling trap, since the unstressed middle vowel gives no clue that it descends from the word for month.

How the word is built

• tri- (three)
• -mester (from Latin mensis: month)
• -er