Av Beit Din

Av Beit Din, Av Beis Din, or Abh Beyth Diyn (abbreviated: AB"D) (Hebrew:אב בית דין‎, "Chief of the Court") was the second-highest-ranking member of the Sanhedrin during the Second Commonwealth period. The president, who bore the title Nasi, was in a way the supervisor, but not a member of the court, which consisted of seventy members. The most learned and important of these seventy members was called Av Beit Din, a title similar to that of vice-president.