Nasi

Nasi the name given by the Jews to the president of the great Sanhedrim, who was held in high respect by the court. Moses is said by the rabbins to have been the first to fill the office. Till the captivity the sovereign or chief ruler acted as Nasi, but after that time the two offices became entirely distinct, the right of holding the office of Nasi belonging to the descendants of Hillel.

⇒See also the International Standard Bible Encyclopedia.