The Sanhedrin (Hebrew and Middle Aramaic סַנְהֶדְרִין, a loanword from Koine Greek: Συνέδριον, romanized: synedrion, 'assembly,' 'sitting together,' hence 'assembly' or 'council') was a Jewish legislative and judicial assembly of either 23 or 70 elders, existing at both a local and central level in the ancient land of Israel.
There were two classes of Rabbinite courts called sanhedrins: Greater and Lesser. A lesser Sanhedrin of 23 judges was appointed to sit as a tribunal in each city. There was only one Great Sanhedrin of 70 judges, which, among other roles, acted as a supreme court, taking appeals from cases that lesser courts decided. In general usage, the Sanhedrin without qualifier usually refers to the Great Sanhedrin, which was presided over by the Nasi, who functioned as its head or representing president, and was a member of the court; the Av Beit Din or the chief of the court, who was second to the Nasi and 69 general members.