/ Thesaurus / P Synonyms of planaria Find synonyms for: Noun1. planarian, planaria, flatworm, platyhelminthusage: free-swimming mostly freshwater flatworms; popular in laboratory studies for the ability to regenerate lost partsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: respite Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language