/ Thesaurus / D Synonyms of d day Find synonyms for: Noun1. D-day, 6 June 1944usage: date of the Allied landing in France, World War IIWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: tactful Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language