Breadcrumb Home > Thesaurus > O Synonyms of ontario Find synonyms for: Noun 1. Lake Ontario, Ontario usage: the smallest of the Great Lakes 2. Ontario usage: a prosperous and industrialized province in central Canada WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of ontario (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Chinese New Year History, Meaning, and Celebrations Current Events This Week: February 2024 Valentine's Day Valentine's Day History Mardi Gras 30 "Charlie and the Chocolate Factory" Quotes ✖ Related Content Daily Word Quiz: soupon Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language