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tri·mes·ter

(trī-mĕstər, trīmĕs′-)

1. A period or term of three months.

2. One of three terms into which an academic year is divided in some universities and colleges.

[French trimestre, from Latin trimēstris, trimēnstris, of three months : tri-, tri- + mēnsis, month; see mē-² in the Appendix of Indo-European roots.]

tri·mestral (-trəl), tri·mestri·al (-trē-əl) adj.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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