sac
noun.
an enclosed space
the trapped miners found a pocket of air
Synonym: pocket, pouch, sack
noun.
a case or sheath especially a pollen sac or moss capsule
Synonym: theca
noun.
a member of the Algonquian people formerly living in Wisconsin in the Fox River valley and on the shores of Green Bay
Synonym: sauk
noun.
a structure resembling a bag in an animal