The Collaborative International Dictionary of English v.0.48:

jumpstart \jump"start`\, Jump-start \Jump"-start`\, v. t.
   1. To start (the engine of a motor vehicle) using a temporary
      connection to supply electrical power from another vehicle
      or another source of current; -- an emergency procedure
      used when a vehicle's own battery has insufficient power
      to start the vehicle normally.

   Note: Cables used to transmit electrical current from one
         vehicle to another for the purpose of jump-starting are
         called jumper cables.
         [PJC]

   2. To provide a speedy start to (an activity) using the
      assistance of some external impetus; to re-energize (an
      activity proceeding sluggishly); -- accomplished by
      application of a stimulus not normally used in the
      activity. [Figurative]
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Jump-start \Jump"-start`\, n.
   The action or event of jump-starting. For motor vehicles, the
   jump-starting of an engine is also called a jump.
   [PJC] Jump suit

WordNet (r) 3.0 (2006):

jumpstart
    n 1: starting an automobile engine that has a weak battery by
         means of jumper cables to another car; "my battery was dead
         so I had to get a jumpstart from my neighbor" [syn:
         jumpstart, jump-start]
    v 1: start (a car engine whose battery is dead) by connecting it
         to another car's battery [syn: jumpstart, jump-start,
         jump]
    2: start or re-start vigorously; "The Secretary of State intends
       to jumpstart the Middle East Peace Process" [syn:
       jumpstart, jump-start]