The act or process of restarting a computer without turning off the power. A warm boot erases everything in RAM and then reloads the operating system into RAM.
warm boot - Computer Definition
Reloading the operating system by performing a Restart operation from the computer's main menu while it is still turned on. The warm boot does not turn the power off and back on, and it does not clear memory. Contrast with cold boot. See boot, clean boot and reboot.