drill1
  
  n.
   - a tool or machine with a rotating or reciprocating cutting tip, used for boring holes.
 - training in military exercises. 
▸instruction by means of repeated exercises.
 ▸
(the drill)
 informal the correct or recognized procedure.
 - a predatory mollusc that bores into the shells of other molluscs. 
[Urosalpinx cinerea (oyster drill, America) and other species.]
 
v.
    - bore (a hole) in something with a drill. 
▸sink a borehole.
 - subject to military training or other intensive instruction.
 - informal (in sport) hit (a shot) hard and in a straight line.
 - 
(drill down)
 Computing  access data in a lower level of a hierarchically structured database.
 
 
  Derivative
  
  Etymology
  C17: from MDu. drillen ‘bore, turn in a circle’.
 
  
    
drill2
  
  n.
 a machine which makes small furrows, sows seed in them, and then covers the sown seed. 
▸a small furrow made by a drill.
v.
 sow with a drill.
 
  Etymology
  C18: perh. from drill1.
 
  
    
drill3
  
  n.
 a West African baboon with a naked blue or purple rump. 
[
Mandrillus leucophaeus.]
 
  Etymology
  C17: prob. a local word; cf. mandrill.
 
  
    
drill4
  
  n.
 a coarse twilled cotton or linen fabric.
 
  Etymology
  C18: abbrev. of earlier drilling, from Ger. Drillich, from L. trilix ‘triple-twilled’, from tri- ‘three’ + licium ‘thread’.