Definition of trimester
1 : a period of three or about three months; especially : any of three periods of approximately three months each into which a human pregnancy is divided
2 : one of three terms into which the academic year is sometimes divided
Examples of trimester in a Sentence
development in the first trimester
Recent Examples of trimester from the Web
The fourth trimester is the first three months of a baby’s life when the mother tries to create a womb-like environment in the real world.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'trimester'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Did You Know?
Semester, which comes from the Latin words for "six" and "month", has come to mean half an academic year when the year is divided into two segments. When an academic year is divided into three segments, each is called a trimester (which is usually a bit more accurate, since each segment often is close to three months in length). Some colleges operate on the "quarter" system, with the summer being the fourth quarter, but this just means that each quarter is basically a trimester. In a human pregnancy, a trimester is three months long, representing one-third of the nine months that a typical pregnancy lasts.
Origin and Etymology of trimester
French trimestre, from Latin trimestris of three months, from tri- + mensis month — more at moon
First Known Use: 1821
TRIMESTER Defined for English Language Learners
Definition of trimester for English Language Learners
: a period of three months; especially : one of three periods into which a woman's pregnancy is often divided
: one of three periods into which an academic year is sometimes divided
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