/ Thesaurus / H Synonyms of hydrogen ion Find synonyms for: Noun1. hydrogen ion, proton, cationusage: a positively charged atom of hydrogen; that is to say, a normal hydrogen atomic nucleusWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: pudgy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language