bootstrap n.

"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].

1610s, "band of leather," from Scottish and/or nautical variant of strope "loop or strap on a harness" (mid-14c.), probably from Old French estrop "strap," from Latin stroppus "strap, band," perhaps via Etruscan, ultimately from Greek strophos "twisted band; a cord, rope," from strephein "to turn" (from PIE root *streb(h)- "to wind, turn"). Old English stropp, Dutch strop "halter" also are borrowed from Latin, and the Old English word might be the source of the modern one. Slang meaning "credit" is from 1828.

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.