/ Thesaurus / E Synonyms of ethmoidal sinus Find synonyms for: Noun1. ethmoid sinus, ethmoidal sinus, sinus ethmoidales, sinususage: a sinus of the meatuses of the nasal cavity (behind the bridge of the nose)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: eccentric Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language