/ Thesaurus / O Synonyms of onion plant Find synonyms for: Noun1. onion, onion plant, Allium cepa, alliaceous plantusage: bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulbWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: cur Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language