Drill \Drill\, n.
   1. An instrument with an edged or pointed end used for making
      holes in hard substances; strictly, a tool that cuts with
      its end, by revolving, as in drilling metals, or by a
      succession of blows, as in drilling stone; also, a drill
      press.
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   2. (Mil.) The act or exercise of training soldiers in the
      military art, as in the manual of arms, in the execution
      of evolutions, and the like; hence, diligent and strict
      instruction and exercise in the rudiments and methods of
      any business; a kind or method of military exercises; as,
      infantry drill; battalion drill; artillery drill.
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   3. Any exercise, physical or mental, enforced with regularity
      and by constant repetition; as, a severe drill in Latin
      grammar.
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   4. (Zool.) A marine gastropod, of several species, which
      kills oysters and other bivalves by drilling holes through
      the shell. The most destructive kind is Urosalpinx
      cinerea.
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   Bow drill, Breast drill. See under Bow, Breast.

   Cotter drill, or Traverse drill, a machine tool for
      drilling slots.

   Diamond drill. See under Diamond.

   Drill jig. See under Jig.

   Drill pin, the pin in a lock which enters the hollow stem
      of the key.

   Drill sergeant (Mil.), a noncommissioned officer whose
      office it is to instruct soldiers as to their duties, and
      to train them to military exercises and evolutions.

   Vertical drill, a drill press.
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