[1] : The Collaborative International Dictionary of English v.0.48

handler \handler\ n.
   1. one who trains or exhibits animals.

   syn: animal trainer.
        wordnet 1.5

   2. someone in charge of training an athlete especially a
      boxer or a team.

   note: the term is used sometimes sarcastically of political
         consultants: "the president's handlers".

   syn: coach, manager.
        wordnet 1.5 +pjc

[2] : WordNet (r) 2.0

handler
     n 1: one who trains or exhibits animals syn: animal trainer
     2: an agent who handles something or someone; "the senator's
        campaign handlers"
     3: sports someone in charge of training an athlete or a team
        syn: coach, manager
see also:
animal trainer coach manager 

[3] : Moby Thesaurus II by Grady Ward, 1.0

18 moby thesaurus words for "handler":
   agent, athletic coach, coach, conductor, driller, drillmaster,
   driver, engineer, functionary, groomer, manipulator, operant,
   operative, operator, pilot, runner, steersman, trainer

Handler >> H Words
Handler, definition of term: Handler
handler_pag1.html