/ Thesaurus / R Synonyms of rainbow cactus Find synonyms for: Noun1. rainbow cactus, cactususage: a stout cylindrical cactus of the southwest United States and adjacent MexicoWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: penurious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language