Breadcrumb Home > Thesaurus > P Synonyms of pentoxide Find synonyms for: Noun1. pentoxide, oxideusage: an oxide containing five atoms of oxygen in the moleculeWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of pentoxide (Dictionary) ✖ Related Content Daily Word Quiz: taradiddle Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language