Twelve Families

The Twelve Families were the 12 most ancient and distinguished Vulcan clans, "the basis of [their] civilization."

Among these clans was that of Surak, from whom Sarek -- and, thus, Sybok and Spock -- was directly descended.

The Shari Tcha'kla was a council and law-enforcement body that monitored members of the Twelve Families on the degree to which they hewed to the Surakian standard. Those who did not were deemed v'tosh ka'tur -- Vulcans who rejected the teachings of Surak, and were without logic. Such individuals were banished from Vulcan society. (Absolute Horizon)