Key \Key\ (k[emac]), n. [OE. keye, key, kay, AS. c[ae]g.]
      1. An instrument by means of which the bolt of a lock is shot
            or drawn; usually, a removable metal instrument fitted to
            the mechanism of a particular lock and operated by turning
            in its place.
  
      2. An instrument which is turned like a key in fastening or
            adjusting any mechanism; as, a watch key; a bed key, etc.
  
      3. That part of an instrument or machine which serves as the
            means of operating it; as, a telegraph key; the keys of a
            pianoforte, or of a typewriter.
  
      4. A position or condition which affords entrance, control,
            pr possession, etc.; as, the key of a line of defense; the
            key of a country; the key of a political situation. Hence,
            that which serves to unlock, open, discover, or solve
            something unknown or difficult; as, the key to a riddle;
            the key to a problem.
  
                     Those who are accustomed to reason have got the true
                     key of books.                                    --Locke.
  
                     Who keeps the keys of all the creeds. --Tennyson.
  
      5. That part of a mechanism which serves to lock up, make
            fast, or adjust to position.
  
      6. (Arch.)
            (a) A piece of wood used as a wedge.
            (b) The last board of a floor when laid down.
  
      7. (Masonry)
            (a) A keystone.
            (b) That part of the plastering which is forced through
                  between the laths and holds the rest in place.
  
      8. (Mach.)
            (a) A wedge to unite two or more pieces, or adjust their
                  relative position; a cotter; a forelock. See Illusts.
                  of {Cotter}, and {Gib}.
            (b) A bar, pin or wedge, to secure a crank, pulley,
                  coupling, etc., upon a shaft, and prevent relative
                  turning; sometimes holding by friction alone, but more
                  frequently by its resistance to shearing, being
                  usually embedded partly in the shaft and partly in the
                  crank, pulley, etc.
  
      9. (Bot.) An indehiscent, one-seeded fruit furnished with a
            wing, as the fruit of the ash and maple; a samara; --
            called also {key fruit}.
  
      10. (Mus.)
            (a) A family of tones whose regular members are called
                  diatonic tones, and named key tone (or tonic) or one
                  (or eight), mediant or three, dominant or five,
                  subdominant or four, submediant or six, supertonic or
                  two, and subtonic or seven. Chromatic tones are
                  temporary members of a key, under such names as [bd]
                  sharp four,[b8] [bd]flat seven,[b8] etc. Scales and
                  tunes of every variety are made from the tones of a
                  key.
            (b) The fundamental tone of a movement to which its
                  modulations are referred, and with which it generally
                  begins and ends; keynote.
  
                           Both warbling of one song, both in one key.
                                                                              --Shak.
  
      11. Fig: The general pitch or tone of a sentence or
            utterance.
  
                     You fall at once into a lower key.   --Cowper.
  
      {Key bed}. Same as {Key seat}.
  
      {Key bolt}, a bolt which has a mortise near the end, and is
            secured by a cotter or wedge instead of a nut.
  
      {Key bugle}. See {Kent bugle}.
  
      {Key of a position} [or] {country.} (Mil.) See {Key}, 4.
  
      {Key seat} (Mach.), a bed or groove to receive a key which
            prevents one part from turning on the other.
  
      {Key way}, a channel for a key, in the hole of a piece which
            is keyed to a shaft; an internal key seat; -- called also
            {key seat}.
  
      {Key wrench} (Mach.), an adjustable wrench in which the
            movable jaw is made fast by a key.
  
      {Power of the keys} (Eccl.), the authority claimed by the
            ministry in some Christian churches to administer the
            discipline of the church, and to grant or withhold its
            privileges; -- so called from the declaration of Christ,
            [bd]I will give unto thee the keys of the kingdom of
            heaven.[b8] --Matt. xvi. 19.

English Dictionary: Kopfaufschlagbereich

by the DICT Development Group