n. A period of three months or about three months.
n. One of the terms of an academic year in those learning institutions that divide their teaching in three roughly equal terms, each about three months long. Compare semester.
the GNU version of the Collaborative International Dictionary of English
n. A term or period of three months.
The Century Dictionary and Cyclopedia
n. A term or period of three months.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. one of three divisions of an academic year
n. a period of three months; especially one of the three three-month periods into which human pregnancy is divided
Word Usage
"You may hear the word trimester period of three months a lot while you’re pregnant."