hydroxide ion hydroxide • hydroximic · · · Info · Definitions · Synonyms · Characters · · hydroxide ion · · Text Common · · Latin · · Scripts 13 · · Length 5 · · Syllables Definitions · · · (noun) the anion OH having one oxygen and one hydrogen atom. Synonyms: hydroxide ion, hydroxyl ion. · · Noun Definition 1 Synonyms · · · hydroxyl ion · · Synonym 1 Characters · · space U+0020 d latin small letter d U+0064 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 x latin small letter x U+0078 y latin small letter y U+0079