1975, transitive, "start up (a computer) by causing an operating system to load in the memory," from bootstrap (v.), a 1958 derived verb from bootstrap (n.) in the sense of "fixed sequence of instructions to load the operating system of a computer" (1953).
This is from the notion of the first-loaded program pulling itself (and the rest) up by the bootstrap. The intransitive use, of a computer operating system, is from 1983. Related: Booted; booting.
"covering for the foot and lower leg," early 14c., from Old French bote "boot" (12c.), with corresponding words in Provençal, Spanish, and Medieval Latin, all of unknown origin, perhaps from a Germanic source. Originally of riding boots only.
From c. 1600 as "fixed external step of a coach." This later was extended to "low outside compartment used for stowing luggage" (1781) and hence the transferred use in Britain in reference to the storage compartment in a motor vehicle (American English uses trunk (n.1)).
Boot-black "person who shines boots and shoes" is from 1817; boot-jack "implement to hold a boot by the heel while the foot is drawn from it" is from 1793. Boot Hill, U.S. frontier slang for "cemetery" (1893, in a Texas panhandle context) probably is an allusion to dying with one's boots on. An old Dorsetshire word for "half-boots" was skilty-boots [Halliwell, Wright].
"profit, use," Old English bot "help, relief, advantage; atonement," literally "a making better," from Proto-Germanic *boto (see better (adj.)). Compare Old Frisian bote "fine, penalty, penance, compensation," German Buße "penance, atonement," Gothic botha "advantage, usefulness, profit." Now mostly in phrase to boot (Old English to bote), indicating something thrown in by one of the parties to a bargain as an additional consideration.
"to kick, drive by kicking," 1877, American English, from boot (n.1). Earlier "to beat with a boot" (a military punishment), 1802. The generalized sense of "eject, kick (out)" is from 1880. To give (someone) the boot "dismiss, kick out" is from 1888. Related: Booted; booting.
1756 as "ale and porter;" as a mixture of milk and cream, by 1946.
"training station for recruits," by 1941, U.S. Marines slang, said to be from boot (n.1) as slang for "recruit," which is attested by 1915 and supposedly dates from the Spanish-American War and is a synecdoche from boots "leggings worn by U.S. sailors."