/ Thesaurus / B Synonyms of barium oxide Find synonyms for: Noun1. barium monoxide, barium oxide, barium protoxide, barytausage: an oxide of barium; a whitish toxic powderWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language