Breadcrumb Home > Thesaurus > I Synonyms of interplanetary Find synonyms for: Adjective1. interplanetaryusage: between or among planets; "interplanetary travel"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of interplanetary (Dictionary) ✖ Related Content Daily Word Quiz: deracinate Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language