/ Thesaurus / C Synonyms of caustic soda Find synonyms for: Noun1. sodium hydroxide, caustic soda, hydroxide, hydrated oxide, lyeusage: a strongly alkaline caustic used in manufacturing soap and paper and aluminum and various sodium compoundsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: effervescent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language