sac

A pouch or pouchlike structure in an organism, sometimes filled with fluid.

In bot., anat., and zoology, a sack, cyst, bag, bursa, pouch, purse, or receptacle of some kind specified by a qualifying word; a saccule; a saccus.

In law, the privilege enjoyed by the lord of a manor of holding courts, trying causes, and imposing fines. Also saccage.