"plan or system of electrical circuits," 1946, from circuit (n.)+ -ry.

abbreviation of public address (system), attested from 1936.

1832, American English, originally "a fire deliberately lit ahead of an advancing wildfire to deprive it of fuel," from back (adj.) + fire (n.). As a verb in this sense, recorded from 1886.

The noun meaning "premature ignition in an internal-combustion engine" is recorded by 1897. As a verb, of schemes, plans, etc., "to affect the initiator rather than the intended object" it is attested from 1912, a figurative use from the accidental back-firing of firearms.

"scientific study of the form and function of the nervous system," 1680s, from Modern Latin neurologia, from Modern Greek neurologia (1660s), from neuro- "nerves, the nervous system" (see neuro-) + -logia "study" (see -logy). Related: Neurological (1755).

"scientific study of the nervous system," 1963, from neuro- + science.

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.

former transliteration of the name of the Chinese capital city, now (in the pinyin system) called Beijing. In the Wade-Giles system it was Peiping; the form Peking pre-dates Wade-Giles and was formed by the old British-run, Hong Kong-based Chinese postal system. Peking duck, "large domestic duck of white plumage and orange beak and legs," is attested from 1880.

"doctrine or system of protection in political economy," 1846, from protectionist + -ism.

"tenets, practices, and religious system of the Sikhs," 1849, from Sikh + -ism.

1873, from ethyl + -ane, the appropriate suffix under Hofmann's system.