The Collaborative International Dictionary of English v.0.48:

Sacs \Sacs\ (s[add]ks), n. pl.; sing. Sac. (Ethnol.)
   A tribe of Indians, which, together with the Foxes, formerly
   occupied the region about Green Bay, Wisconsin. [Written also
   Sauks.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sac \Sac\ (s[add]k), n. (Ethnol.)
   See Sacs.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sac \Sac\, n. [See Sake, Soc.] (O.Eng. Law)
   The privilege formerly enjoyed by the lord of a manor, of
   holding courts, trying causes, and imposing fines. --Cowell.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sac \Sac\ (s[a^]k), n. [F., fr. L. saccus a sack. See Sack a
   bag.]
   1. See 2d Sack.
      [1913 Webster]

   2. (Biol.) A cavity, bag, or receptacle, usually containing
      fluid, and either closed, or opening into another cavity
      to the exterior; a sack.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sac
    n 1: an enclosed space; "the trapped miners found a pocket of
         air" [syn: pouch, sac, sack, pocket]
    2: a case or sheath especially a pollen sac or moss capsule
       [syn: theca, sac]
    3: a member of the Algonquian people formerly living in
       Wisconsin in the Fox River valley and on the shores of Green
       Bay [syn: Sauk, Sac]
    4: a structure resembling a bag in an animal

The Free On-line Dictionary of Computing (19 January 2023):

SAC

   1. An early system on the Datatron 200 series.

   [Listed in CACM 2(5):16 (May 1959)].

   (1995-04-12)

   2. Service Access Controller.

   (2002-12-30)