The Sanhedrin, from the Greek term sunedrion (which means, literally, "sitting together") was the Jewish high council. It addressed both judicial and administrative matters.
Members (there were seventy-one) of the Sanhedrin (which included men from the high-priestly family, scribes/religious experts and lay elders) sat in a semicircle so everyone could see each other. Carefully selected judges, these individuals had to be knowledgable in many areas (so they could apply Torah law to all possible situations).
Image above, from People's Cyclopedia of Universal Knowledge (1883).