Breadcrumb Home > Thesaurus > O Synonyms of os frontale Find synonyms for: Noun1. frontal bone, os frontale, forehead, membrane boneusage: the large cranial bone forming the front part of the cranium: includes the upper part of the orbitsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. ✖ Related Content Daily Word Quiz: triumphalism Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language