1. A container, case, or receptacle, usually rectangular, of wood, metal, cardboard, etc., and often with a lid or removable cover
It's Boxing Day today, so why not?
Box comes from Old English box ("a wooden container" or "type of shrub"), which was borrowed from Late Latin buxis. Buxis was taken from Greek pyxis ("boxwood box") from pyxos ("box tree"). Before that, the origin is uncertain. The slang meaning "vulva" dates back to the 17th century.
Box meaning "a blow" is unrelated. It dates to the 1300's and is of uncertain origin. I may be related to Dutch boke, Middle High German buc and Danish bask, all of which mean "a blow." The verb to box dates to the 1560's and boxing as a sport is first attested in 1711.