indigotin Syllabification: (in·dig·o·tin)Pronunciation: /inˈdigətin, ˌindəˈgōtn/Definition of indigotin noun Chemistry a dark blue crystalline compound that is the main constituent of the dye indigo. Chemical formula: (C8H6NO)2 Origin: mid 19th century: from indigo + -t- (for ease of pronunciation) + -in1indigotin in other Oxford dictionaries Definition of indigotin in the British & World English dictionary