Source : Webster's Revised Unabridged Dictionary (1913)

Collaboration \Col*lab`o*ra"tion\, n.
   The act of working together; united labor.

Source : WordNet®

collaboration
     n 1: act of working jointly; "they worked either in collaboration
          or independently" [syn: {coaction}]
     2: act of cooperating traitorously with an enemy that is
        occupying your country [syn: {collaborationism}, {quislingism}]