trimester

noun
tri·​mes·​ter | \ (ˌ)trī-ˈme-stər How to pronounce trimester (audio) , ˈtrī-ˌ \

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

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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

development in the first trimester
Recent Examples on the Web Research from Northwestern found that people who were vaccinated earlier in their third trimester had a higher likelihood of passing antibodies to their babies than those who got their shot closer to delivery. Natalie Gontcharova, refinery29.com, 20 May 2021 In fact, women who were vaccinated early in their third trimester had a better chance of passing protective antibodies to their newborns than women who were vaccinated closer to their delivery date. Sandee Lamotte, CNN, 11 May 2021 Vanessa’s child suffered from a rare chromosome disorder in her second trimester. Cassell Ferere, Forbes, 6 May 2021 This week, our listener question is from Stasia, a Black mom-to-be in her third trimester. Zahra Barnes, SELF, 26 Apr. 2021 The study mostly included women in their third trimester. Meredith Deliso, ABC News, 22 Apr. 2021 But late-term, third-trimester abortions must be performed in hospitals that have anesthesiology and obstetrics departments. Christopher Keating, courant.com, 6 Oct. 2018 Rejecting the shot Anne Marie Wallace, 29, on Monday visited Dr. Waits’s Centreville clinic in her first trimester of pregnancy. al, 6 May 2021 Several states allow these nurses to conduct first trimester abortions, including California, Colorado, Maine, Massachusetts, Montana, New Hampshire, Virginia, Vermont, and West Virginia. Kaelan Deese, Washington Examiner, 13 Apr. 2021

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.

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First Known Use of trimester

1821, in the meaning defined at sense 1

History and Etymology for trimester

French trimestre, from Latin trimestris of three months, from tri- + mensis month — more at moon

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Time Traveler for trimester

Time Traveler

The first known use of trimester was in 1821

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Statistics for trimester

Last Updated

7 Jun 2021

Cite this Entry

“Trimester.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/trimester. Accessed 13 Jun. 2021.

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More Definitions for trimester

trimester

noun

English Language Learners Definition of trimester

: a period of three months especially : one of three periods into which a woman's pregnancy is often divided
US : one of three periods into which an academic year is sometimes divided

trimester

noun
tri·​mes·​ter | \ (ˈ)trī-ˈmes-tər How to pronounce trimester (audio) , ˈtrī-ˌ How to pronounce trimester (audio) \

Medical Definition of trimester

: 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

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