The Collaborative International Dictionary of English v.0.48:

Accelerate \Ac*cel"er*ate\, v. t. [imp. & p. p. Accelerated;
   p. pr. & vb. n. Accelerating.] [L. acceleratus, p. p. of
   accelerare; ad + celerare to hasten; celer quick. See
   Celerity.]
   1. To cause to move faster; to quicken the motion of; to add
      to the speed of; -- opposed to retard.
      [1913 Webster]

   2. To quicken the natural or ordinary progression or process
      of; as, to accelerate the growth of a plant, the increase
      of wealth, etc.
      [1913 Webster]

   3. To hasten, as the occurence of an event; as, to accelerate
      our departure.
      [1913 Webster]

   Accelerated motion (Mech.), motion with a continually
      increasing velocity.

   Accelerating force, the force which causes accelerated
      motion.                                     --Nichol.
      [1913 Webster]

   Syn: To hasten; expedite; quicken; dispatch; forward;
        advance; further.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

accelerated \accelerated\ adj.
   1. 1 caused to move faster

   Syn: speeded up
        [WordNet 1.5 +PJC]

   2. 1 caused to be completed in a shorter than normal time
      period; speeded up, as of an academic course; He took an
      accelerated curriculum, and graduated in three years.
      Opposite of delayed.

   Syn: expedited
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

accelerated
    adj 1: speeded up, as of an academic course; "in an accelerated
           program in school"