What does Boxing Day have to do with boxing?
mid-15c., "instrument for crushing or pounding," from Middle Dutch braeke "flax brake," from breken "to break" (see break (v.)). The word was applied to many crushing implements and to the ring through the nose of a draught ox. It was influenced in sense by Old French brac, a form of bras "an arm," thus "a lever or handle," which was being used in English from late 14c., and applied to "a bridle or curb" from early 15c. One or the other or both took up the main modern meaning of "stopping device for a wheel," first attested 1772.
kind of fern, early 14c.; see bracken.
"to apply a brake to a wheel," 1868, from brake (n.1). Earlier, "to beat flax" (late 14c.). Related: Braked; braking.