Hindustan, a name sometimes loosely applied to the entire Indian peninsula, but which, strictly speaking, embraces only the country of the upper valley of the Ganges, divided into NW. Provinces, Oude, and Behar; the language spoken is Hindi, a pure Sanskritic tongue, on which Hindustani is based, but with large Persian and Arabic admixtures.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Hinduism * Hindustani