/ Thesaurus / U Synonyms of upstair Find synonyms for: Adjective1. upstairs (vs. downstairs), upstairusage: on or of upper floors of a building; "the upstairs maid"; "an upstairs room"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language