WordWeb Online

1. Used especially of drugs or muscles that work together so the total effect is greater than the sum of the two (or more)
   - interactive
    
2. Of or relating to the theological doctrine of synergism
    
3. Working together; used especially of groups, as subsidiaries of a corporation, cooperating for an enhanced effect
   "a synergistic effect";
   - synergetic

See also: cooperative

Antonym: antagonistic

Encyclopedia: Synergistic