The Jargon File (version 4.4.7, 29 Dec 2003):

warm boot
 n.

    See boot.


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

warm boot

    A boot from power on, where the CPU
   and peripherals are already powered up (warm).

   A warm boot might be performed after a software crash or
   a hardware reset.

   Contrast cold boot.  See also reboot.

   [Jargon File]

   (1998-04-28)