(1):

(n.) The seat of a judge; the bench on which a judge and his associates sit for administering justice.

(2):

(n.) Hence, a court or forum; as, the House of Lords, in England, is the highest tribunal in the kingdom.

(3):

(n.) In villages of the Philippine Islands, a kind of townhall. At the tribunal the head men of the village met to transact business, prisoners were confined, and troops and travelers were often quartered.