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.
      1913 webster

   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.
      1913 webster

   3. any exercise, physical or mental, enforced with regularity
      and by constant repetition; as, a severe drill in latin
      grammar.
      1913 webster

   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.
      1913 webster

   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.
      1913 webster
see also:
urosalpinx cinerea bow drill breast drill bow breast cotter drill 
traverse drill diamond drill diamond drill jig jig 
drill pin drill sergeant vertical drill