Indianapolis Syllabification: (In·di·an·ap·o·lis)Pronunciation: /ˌindēəˈnapələs/Definition of Indianapolis the capital of Indiana, in the central part of the state; population 798,382 (est. 2008). The city hosts the Indy 500, an annual 500-mile (804.5-km) car race. Indianapolis in other Oxford dictionaries Definition of Indianapolis in the British & World English dictionary