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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