A Gotra indicates lineage in the Hindu community. Gotra is used as surname in many castes. Each of the gotras is normally named after a great ancient Rishi, and belonging to a particular gotra generally implies patrilineal descension from the rishi, whom the gotra is named after. It is believed that the custom originated to enable one to identify and honor one's ancestors, and was later extended for use in rituals. Typically, men retain the gotra of their father, and women take the gotra of their husband after their wedding.

Present day gotras in the Brahmin caste derive from eight rishis, Agastya and the Saptarishis - Atri, Bharadwaja, Gautama , Jamadagni, Kasyapa, Vasishta, and Viswamitra. Over time, the number of gotras have increased and today, by some counts, number between 50 and 100. A sub-division of the gotra is a pravara, which is a set of the greatest rishis who belonged to the gotra.

The gotra-pravara classification made exogamous systems feasible. Even in ancient times, marriages within pravaras, and according to some scriptures, that within gotras, were not permitted.

The gotra system initially was used within the Brahmin caste. But in modern times, other castes in the Hindu community have adopted the gotra system or variants of it for their customs.

References

• gsbkerala.com
• Marriage Ceremonies
• Gotra