/ Thesaurus / O Synonyms of onopordum acanthium Find synonyms for: Noun1. cotton thistle, woolly thistle, Scotch thistle, Onopordum acanthium, Onopordon acanthium, thistleusage: biennial Eurasian white hairy thistle having pale purple flowers; naturalized in North AmericaWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: ontiguous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language