Breadcrumb Home > Thesaurus > O Synonyms of oak apple Find synonyms for: Noun1. oak apple, gallusage: oak gall caused by larvae of a cynipid waspWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. ✖ Related Content Daily Word Quiz: prandial Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language