Breadcrumb Home > Thesaurus Cite Synonyms of eighteenth Find synonyms for: Noun1. eighteenth, rankusage: position 18 in a countable series of thingsAdjective1. eighteenth, 18th, ordinal (vs. cardinal)usage: coming next after the seventeenth in positionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.See also: eighteenth (Dictionary) Related Content Daily Word Quiz: persiflage Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language Synonyms Index