Wikipedia
In Brahmin Hindu culture, a Pravara (Sanskrit for "most excellent") is a particular Brahmin's descent from a rishi (sage) who belonged to their gotra (clan). In vedic ritual, the importance of the pravara appears to be in its use by the ritualist for extolling his ancestry and proclaiming, "as a descendant of worthy ancestors, I am a fit and proper person to do the act I am performing." Generally, there are three,five or seven pravaras. The sacred thread yajnopavita worn on upanayana has close and essential connection with the concept of pravaras related to Brahmin gotra system. While tying the knots of sacred thread, an oath is taken in the name of each one of these three,five or seven of the most excellent rishis belonging to one's gotra.
The full affiliation of a brāhamana consists of (1) gotra, (2)sutra (of Kalpa), (3) shakha, (4)pravaras .
(Example :) A brahmana named 'Rama' introduces himself as follows : I am 'Rama', of Shrivatsa gotra, of Āpastamba sutra, of Taittiriya shākha of Yajurveda, of five pravaras named Bhārgava, Chyāvana, Āpnavan, Aurva and Jāmdagnya (This example is based upon the example given by Pattābhirām Shastri in the introduction to Vedārtha-Pārijata, cf. ref.).
While the gotras were classified initially according to seven rishis, the pravaras were classified under the names of the following seven rishis:
- Agastya
- Angirasa
- Atri
- Bhrigu
- Kashyapa
- Vashista
- Vishvamitra
According to the listing of authors included in the verses in Rigved, the rishi Jamadagni was a descendant of rishi Bhrigu while the rishis Gautam and Bharadvaja were the descendants of rishi Angirasa.
The pravara identifies the association of a person with two, three (or sometimes five) of the above-mentioned rishis. It also signifies the Sutras contributed to different Vedas by those rishis.
For example, Kashyapa Gothram has 3 rishis associated with it viz. Kashyap, Nidruva and Avatsara