WordWeb Online

1. Cooperate or pretend to cooperate
   "He decided to play ball with the burglars for the moment"
   - play along, go along
    
2. Perform an accompaniment to
   - play along, accompany, follow
    
3. An expression used at the beginning of a game of baseball, or to mark the beginning of anything tumultuous

Type of: collaborate, cooperate, co-operate, get together, join forces, play