/ Thesaurus / L Synonyms of lunar day Find synonyms for: Noun1. lunar day, dayusage: the period of time taken for the moon to make one full rotation on its axis (about 27.3 sidereal days)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: heifer Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language