: the act of booting or rebooting a computer or the process by which a computer is booted see bootentry 4 sense 5b
A cold boot is starting up a computer whose power has been turned off. A warm boot involves restarting the system while it is running … J. D. Biersdorfer
Middle English bot, bote "advantage, good, relief, deliverance, redemption, amends, cure," Old English bōt "a making good, repair, relief, deliverance, remedy, improvement, atonement, penance, compensation," going back to Germanic *botō "improvement" — more at better entry 1
Note: Though its Old and Middle English predecessors were common nouns with numerous senses, boot now occurs rarely outside of the idiom to boot. This phrase is attested in the sense "to the advantage (of someone)" in Middle English ("to youre bote") and hence was generalized to "as an extra thing, into the bargain" and then "in addition, moreover."
Verb (1)
Middle English boten "to cure, relieve, add to equalize the value of things exchanged, be of use, avail," probably in part derivative of bot, bote "advantage, good, relief," in part going back to Old English botian "to recover from ill health, keep in repair," derivative of bōt "a making good, repair, relief" — more at boot entry 1
Noun (2)
(senses 1-8) Middle English bote, bot, boot, borrowed from Anglo-French bote (also continental Old French bote, botte), of uncertain origin; (sense 9) noun derivative of boot entry 4, sense 5
Note: The French word is traced to a putative Germanic base *butt- "blunt" in Französisches etymologisches Wörterbuch, along with a diverse group of phonetically similar words, but both the semantic and phonetic assumptions are questionable.
Verb (2)
(senses 1-4) Middle English boten "to put boots on," derivative of bote, botboot entry 3; (sense 5) short for bootstrap in sense "to perform a bootstrap operation," derivative of bootstrap entry 2