18TH Antonyms There are 14 antonyms of the abbr 18th. (opposite meanings)Did you mean?Definition of 18THSynonyms of 18THBest Opposite Words For 18THTop 20Top 10 Top 20 (Default)Top 50 Top 100 All All (Default)WordsPhrases All All (Default)Verb Noun Adjective Adverb RankWordSave?Synonyms..UsageType117thnoun, adjectiven, adj219thadjectiveadj320thnoun, adjectiven, adj421stadjectiveadj522nd623rdnoun, adjectiven, adj724thnoun, adjectiven, adj825thadjectiveadj926thadjectiveadj1027thadjectiveadj1128thnounn1229thnounn1330thadjectiveadj1431st