/ Thesaurus / I Synonyms of interplanetary medium Find synonyms for: Noun1. interplanetary medium, interplanetary spaceusage: interplanetary space including forms of energy and gas and dustWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: devout Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language