spar1
  
  n.
 a thick, strong pole such as is used for a mast or yard on a ship. 
▸the main longitudinal beam of an aircraft wing.
 
  Etymology
  ME: shortening of OFr. esparre, or from ON sperra.
 
  
    
spar2
  
  v.
 (spars, sparring, sparred)
   - make the motions of boxing without landing heavy blows, as a form of training.
 - engage in argument without marked hostility.
 - (of a gamecock) fight with the feet or spurs.
 
n.
  - a period or bout of sparring.
 - informal a close friend.
 
 
  Etymology
  OE sperran, spyrran ‘strike out’, of unknown origin.
 
  
    
spar3
  
  n.
 a crystalline, easily cleavable, translucent or transparent mineral.
 
  Derivative
  
  Etymology
  C16: from Mid. Low Ger.