What does Boxing Day have to do with boxing?
late 14c., from Middle English maked, from Old English macod "made," past participle of macian "to make" (see make). Made up "invented" is from 1789; of minds, "settled, decided," from 1873. To be a made man is in Marlowe's "Faust" (1590). To have it made (1955) is American English colloquial.