Source : Webster's Revised Unabridged Dictionary (1913)

Snack \Snack\, n. [See {Snatch}, v. t.]
   1. A share; a part or portion; -- obsolete, except in the
      colloquial phrase, {to go snacks}, i. e., to share.

            At last he whispers, ``Do, and we go snacks.''
                                                  --Pope.

   2. A slight, hasty repast. [Colloq.]

Source : WordNet®

snack
     n : a light informal meal [syn: {bite}, {collation}]
     v : eat a snack; eat lightly; "She never loses weight because
         she snacks between meals" [syn: {nosh}]