/ Thesaurus / C Synonyms of canker sore Find synonyms for: Noun1. canker, canker sore, ulcer, ulcerationusage: an ulceration (especially of the lips or lining of the mouth)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language