/ Thesaurus / V Synonyms of vacuum flask Find synonyms for: Noun1. vacuum flask, vacuum bottle, flaskusage: flask with double walls separated by vacuum; used to maintain substances at high or low temperaturesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language