trimester
n.one of the three periods that a pregnancy is divided into. It can also mean one of three terms in a school or university year.
n.a period of three months, especially as a division of the duration of human pregnancy. Also refers to one of three terms into which an academic year is divided at some institutions.
“She is currently in her second trimester of pregnancy.”
“The university switched from a semester system to a trimester system to allow for a shorter summer break.”
“During the first trimester, the developing embryo is particularly vulnerable to environmental factors, making prenatal care and nutrition critical during these initial twelve weeks.”
Commonly used with ordinal numbers such as 'first', 'second', or 'third'.
“By the time they end up in Maryland, they’re frequently past the second trimester.”
“In the first trimester, both hormones rise fast.”
PIE word *tréyes From French trimestre, from Latin trimestris (“of three months”), from trēs (“three”) + mensis (“month”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.