What does Boxing Day have to do with boxing?
c.1300, from Old French crucifer (12c., Modern French crucifier), from Vulgar Latin *crucificare, from Late Latin crucifigere "to fasten to a cross," from cruci, dative of Latin crux "cross" (see cross (n.)) + figere "fasten" (see fix (v.)). An ancient mode of capital punishment considered especially ignominious by the Romans. Figurative sense of "to torment" is 1620s. Related: Crucified; crucifying.