/ Thesaurus / S Synonyms of square sail Find synonyms for: Noun1. square sail, sail, canvas, canvass, sheetusage: a four-sided sail set beneath a horizontal yard suspended at the middle from a mastWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: eccentric Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language