/ Thesaurus / D Synonyms of downstair Find synonyms for: Adjective1. downstairs (vs. upstairs), downstair, ground-floorusage: on or of lower floors of a building; "the downstairs (or downstair) phone"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language