[key] n [ME, fr. OE caeg; akin to OFris kei key] (bef. 12c) 1 a: a usu. metal instrument by which the bolt of a lock is turned b: any of various devices having the form or function of such a key
2. a: a means of gaining or preventing entrance, possession, or control b: an instrumental or deciding factor 3 a: something that gives an explanation or identification or provides a solution "the ~ to a riddle" b: a list of words or phrases giving an explanation of symbols or abbreviations c: an aid to interpretation or identification: clue d: an arrangement of the salient characters of a group of plants or animals or of taxa designed to facilitate identification e: a map legend
4. a (1): cotter pin (2): cotter b: a keystone in an arch c: a small piece of wood or metal used as a wedge or for preventing motion between parts
5. a: one of the levers of a keyboard musical instrument that actuates the mechanism and produces the tones b: a lever that controls a vent in the side of a woodwind instrument or a valve in a brass instrument c: a part to be depressed by a finger that serves as one unit of a keyboard
6: samara 7: a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic "the ~ of G major"
8. a: characteristic style or tone b: the tone or pitch of a voice c: the predominant tone of a photograph with respect to its lightness or darkness 9: a decoration or charm resembling a key 10: a small switch for opening or closing an electric circuit "a telegraph ~" 11: the set of instructions governing the encipherment and decipherment of messages 12: a free-throw area in basketball -- keyed adj -- key.less adj
key vt (14c) 1: to lock with or as if with a key: fasten: as a: to secure (as a pulley on a shaft) by a key b: to finish off (an arch) by inserting a keystone
2: to regulate the musical pitch of
3: to bring into harmony or conformity: make appropriate: attune "remarks ~ed to a situation"
4: to identify (a biological specimen) by a key
5: to provide with identifying or explanatory cross-references "instructions ~ed to accompanying drawings --John Gartner"
6: to make nervous, tense, or excited--usu. used with up "was ~ed up over her impending operation" 7: keyboard--often used with in ~ vi 1: to use a key
2: to observe the position or movement of an opposing player in football in order to anticipate the play--usu. used with on
3: keyboard key adj (1913): important, fundamental "~ issues" key n [Sp cayo, fr. Taino] (1697): a low island or reef; specif: any of the coral islets off the southern coast of Florida key n [by shortening & alter. fr. kilo] (1968) slang: a kilogram esp. of marijuana or heroin