"fist-fighter, pugilist," late 15c., agent noun from box (v.2). The breed of dog (1934), is from German Boxer (the breed originated in Germany), itself taken from English boxer "fighter;" the dog so called for its pugnaciousness. Boxer shorts (1943) so called from their resemblance to the attire worn in the ring.
bow-wow
bowyer
box
boxcar
box-cutter
boxer
Boxer Rebellion
boxiana
boxing
Boxing Day
box-kite