eighteenth eighteenmo • eighteenthly · · · Info · Definitions · Synonyms · Characters · · eighteenth · · Text Latin · · Script 10 · · Length Definitions · · · (noun) position 18 in a countable series of things. · · Noun Definition 1 (adj) coming next after the seventeenth in position. Synonyms: 18th. · · Adjective Definition 1 Synonyms · · · 18th · · Synonym 1 Characters · · e latin small letter e U+0065 g latin small letter g U+0067 h latin small letter h U+0068 i latin small letter i U+0069 n latin small letter n U+006E t latin small letter t U+0074