power of the keys, the authority of a pope in ecclesiastical matters, vested in him as successor of St. Peter.

Origin of key

before 900; Middle English key(e), kay(e), Old English cǣg, cǣge; cognate with Old Frisian kei, kai
Can be confusedcay key quay

Synonyms for key Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for key up

key up


(tr, adverb) to raise the intensity, excitement, tension, etc, of




a metal instrument, usually of a specifically contoured shape, that is made to fit a lock and, when rotated, operates the lock's mechanism
any instrument that is rotated to operate a valve, clock winding mechanism, etc
a small metal peg or wedge inserted into keyways
any of a set of levers operating a typewriter, computer, etc
any of the visible parts of the lever mechanism of a musical keyboard instrument that when depressed set in motion the action that causes the instrument to sound
  1. Also called: tonalityany of the 24 major and minor diatonic scales considered as a corpus of notes upon which a piece of music draws for its tonal framework
  2. the main tonal centre in an extended compositiona symphony in the key of F major
  3. the tonic of a major or minor scale
  4. See tuning key
something that is crucial in providing an explanation or interpretationthe key to adult behaviour lies in childhood
a means of achieving a desired endthe key to happiness
a means of access or controlGibraltar is the key to the Mediterranean
a list of explanations of symbols, codes, etc
a text that explains or gives information about a work of literature, art, or music
Also called: key move the correct initial move in the solution of a set problem
biology a systematic list of taxonomic characteristics, used to identify animals or plants
photog painting the dominant tonal value and colour intensity of a pictureSee also low-key (def. 3), high-key
electrical engineering
  1. a hand-operated device for opening or closing a circuit or for switching circuits
  2. a hand-operated switch that is pressed to transmit coded signals, esp Morse code
the grooving or scratching of a surface or the application of a rough coat of plaster, etc, to provide a bond for a subsequent finish
pitchhe spoke in a low key
a characteristic mood or stylea poem in a melancholic key
level of intensityshe worked herself up to a high key
railways a wooden wedge placed between a rail and a chair to keep the rail firmly in place
a wedge for tightening a joint or for splitting stone or timber
botany any dry winged fruit, esp that of the ash
(modifier) photog determining the tonal value of a photographflesh colour is an important key tone


of great importance; cruciala key issue

verb (mainly tr)

(foll by to) to harmonize (with)to key one's actions to the prevailing mood
to adjust or fasten with a key or some similar device
to provide with a key or keys
to scratch the paintwork of (a car) with a key
(often foll by up) to locate the position of (a piece of copy, artwork, etc) on a layout by the use of symbols
(also intr) another word for keyboard (def. 3)
to include a distinguishing device in (an advertisement, etc), so that responses to it can be identified
to provide a keystone for (an arch)
See also key in, key up
Derived Formskeyless, adjective

Word Origin for key

Old English cǣg; related to Old Frisian kēi, Middle Low German keie spear




a variant spelling of cay



John (Phillip). born 1961, New Zealand politician; prime minister from 2008
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for key up



"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).

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for key up



See cay.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for key up


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.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with key up

key up

Make intense, excited, or nervous. For example, The excitement of the gallery opening has really keyed her up. This usage alludes to key in the sense of “wind up a spring-driven mechanism such as a clock.” [Late 1800s]


In addition to the idiom beginning with key

  • key up

also see:

  • in key
  • under lock and key
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.