set theory setterwort • setting · · · Info · Definitions · Characters · · set theory · · Text Common · · Latin · · Scripts 10 · · Length 4 · · Syllables Definitions · · · (noun) the branch of pure mathematics that deals with the nature and relations of sets. Synonyms: set theory. · · Noun Definition 1 Characters · · space U+0020 e latin small letter e U+0065 h latin small letter h U+0068 o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074 y latin small letter y U+0079