What does Boxing Day have to do with boxing?
Old English beald (West Saxon), bald (Anglian) "bold, brave, confident, strong," from Proto-Germanic *balthaz (cf. Old High German bald "bold, swift," in names such as Archibald, Leopold, Theobald; Gothic balþei "boldness;" Old Norse ballr "frightful, dangerous"), perhaps from PIE *bhol-to- suffixed form of *bhel- (2) "to blow, swell" (see bole).
Of flavors (coffee, etc.) from 1829. The noun meaning "those who are bold" is from c.1300. Old French and Provençal baut "bold," Italian baldo "bold, daring, fearless" are Germanic loan-words.