Jati

Jati: Caste - A Jati is a group of people who identify themselves as a separate group. The group may share ancestry, occupation or regional associations. You cannot change your caste in your lifetime but can be reborn into another caste.

Jati literally, means the birth group. Basic endogamous unit of the caste system. There are approximately 3,000 jatis in contemporary Indian society. The word jati is also sometimes used for ethnic, religious, or linguistic groups http://www.kamat.com/indica/caste/