trimester
noun
ˈtrī-ˌme-
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.
Examples of trimester in a Sentence
Mike Valerio, CNN Money, 19 Apr. 2026
The lack of an association persisted after researchers accounted for individual risk factors including the dose of the drug and the trimester of pregnancy in which it was used, the report said.
—Nancy Lapid, USA Today, 16 Apr. 2026
Pregnant women from the second trimester onward should also avoid it, as the growing uterus can compress the inferior vena cava.
—Allison Palmer, Fort Worth Star-Telegram, 9 Apr. 2026
Hesty is in her late second trimester, and her due date is in late May, according to the zoo.
—Katie Langford, Denver Post, 27 Mar. 2026
See All Example Sentences for trimester
Cite this Entry
“Trimester.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/trimester. Accessed 27 Apr. 2026.
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trimester
noun
ˈtrī-ˌ
