"metal piece that works a lock," from Old English cæg "key," of unknown origin, with no certain cognates other than Old Frisian kei. Perhaps related to Middle Low German keie "lance, spear" on notion of "tool to cleave with," from Proto-Germanic *ki- "to cleaver, split" (cf. German Keil "wedge," Gothic us-kijans "come forth," said of seed sprouts, keinan "to germinate"). But Liberman writes, "The original meaning of *kaig-jo- was presumably '*pin with a twisted end.' Words with the root *kai- followed by a consonant meaning 'crooked, bent; twisted' are common only in the North Germanic languages." Modern pronunciation is a northern variant predominating from c.1700; earlier it was often spelled and pronounced kay.
Figurative sense of "that which serves to open or explain" was in Old English; meaning "that which holds together other parts" is from 1520s. As "answer to a test," it is from chess, short for key move, "first move in a solution to a set problem." Musical sense of "tone, note" is 15c., but modern sense of "scale" is 1580s, probably as a translation of Latin clavis or French clef (see clef; also cf. keynote). Extended c.1500 to "mechanism on a musical instrument." As a verb meaning "to scratch (a car's paint job) with a key" it is recorded by 1986.
"low island," 1690s, from Spanish cayo "shoal, reef," from Taino cayo "small island;" spelling influenced by Middle English key "wharf" (c.1300), from Old French kai "sand bank" (see quay).
The main or central note of a piece of music (or part of a piece of music). Each key has its own scale, beginning and ending on the note that defines the octave of the next scale. The key of C-major uses a scale that starts on C and uses only the white keys of the piano. In a piece composed in the key of C, the music is likely to end on the note C, and certain combinations of notes based on C will predominate.
To vandalize a car by scratching it with a key: Well, did you key her car? (1980s+)
A kilogram (about 2.2 pounds) of a narcotic: enough opium to produce a key (kilo) of heroin/ Anybody who can handle a key of pure coke is dealing big
[Narcotics; fr kilo]
frequently mentioned in Scripture. It is called in Hebrew _maphteah_, i.e., the opener (Judg. 3:25); and in the Greek New Testament _kleis_, from its use in shutting (Matt. 16:19; Luke 11:52; Rev. 1:18, etc.). Figures of ancient Egyptian keys are frequently found on the monuments, also of Assyrian locks and keys of wood, and of a large size (comp. Isa. 22:22). The word is used figuratively of power or authority or office (Isa. 22:22; Rev. 3:7; Rev. 1:8; comp. 9:1; 20:1; comp. also Matt. 16:19; 18:18). The "key of knowledge" (Luke 11:52; comp. Matt. 23:13) is the means of attaining the knowledge regarding the kingdom of God. The "power of the keys" is a phrase in general use to denote the extent of ecclesiastical authority.