index case index bar • index center · · · Info · Definitions · Characters · · index case · · Text Common · · Latin · · Scripts 10 · · Length 3 · · Syllables Definitions · · · (noun) the earliest documented case of a disease that is included in an epidemiological study. Synonyms: index case. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 e latin small letter e U+0065 i latin small letter i U+0069 n latin small letter n U+006E s latin small letter s U+0073 x latin small letter x U+0078