资料来源 : pyDict

概率几乎正确

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Pac \Pac\, n.
   A kind of moccasin, having the edges of the sole turned up
   and sewed to the upper. --Knight.

资料来源 : WordNet®

PAC
     n : committee formed by a special-interest group to raise money
         for their favorite political candidates [syn: {political
         action committee}]