key \key\, v. t. imp.  p. p. keved; p. pr.  vb. n.
   keying.
   1. to fasten or secure firmly; to fasten or tighten with keys
      or wedges. --francis.
      1913 webster

   2. computers to enter text, data using keys, especially
      those on a keyboard; to keyboard; as, to key the data in
      by hand.
      pjc

   3. to adjust so as to be maximally effective in a particular
      situation; -- of actions, plans, or speech; as, to key
      one's campaign speech to each local audience.
      pjc

   4. to furnish with a key or keys.
      pjc

   to key up.
      a arch. to raise the whole ring of an arch off its
          centering, by driving in the keystone forcibly.
      b mus. to raise the pitch of.
      c hence, fig., to produce nervous tension in; as, the
          whole team was keyed up for the championship game.
          1913 webster
see also:
keved keying to key up