1662, from Pers. Hindu (adj. & noun) "Indian," from Hind "India," from Skt. sindhu "river," specifically the Indus; hence "region of the Indus," gradually extended across northern India. Hinduism, blanket term for "polytheism of India," is from 1829. The Hindu Kush mountain range means lit. "Indian killer," and was said to have been originally the name given by the Persians to a pass where their Indian slaves had perished in winter.