Breadcrumb Home > Thesaurus > O Synonyms of or Find synonyms for: Noun 1. Oregon, Beaver State, OR usage: a state in northwestern United States on the Pacific 2. operating room, OR, operating theater, operating theatre, surgery, hospital room usage: a room in a hospital equipped for the performance of surgical operations; "great care is taken to keep the operating rooms aseptic" WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of or (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 12 Steps to a New Year New Year's Resolution to Slim Down? Martin Luther King Speeches Books of the Bible: Old Testament Books in Order ✖ Related Content Daily Word Quiz: antecedent Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language