/ Thesaurus / 3 Synonyms of 30th Find synonyms for: Adjective1. thirtieth, 30th, ordinal (vs. cardinal)usage: coming next after the twenty-ninth in positionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: denizen Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language