WordNet (r) 3.0 (2006):

reboot
    v 1: cause to load (an operating system) and start the initial
         processes; "boot your computer" [syn: boot, reboot,
         bring up]

The Free On-line Dictionary of Computing (30 December 2018):

reboot

    (From boot) A boot with the implication
   that the computer has not been down for long, or that the
   boot is a bounce intended to clear some state of
   wedgitude.

   See warm boot.

   (1995-11-27)