Hindus (Hindustani: [ˈɦɪndu] ; ; also known as Sanātanīs) are people who religiously adhere to Hinduism, also known by its endonym Sanātana Dharma. Historically, the term has also been used as a geographical, cultural, and later religious identifier for people living in the Indian subcontinent. It is assumed that the term "Hindu" traces back to Avestan scripture Vendidad which refers to land of seven rivers as Hapta Hendu which itself is a cognate to Sanskrit term Sapta Sindhuḥ.
https://en.wikipedia.org/wiki/Hindus