What does Boxing Day have to do with boxing?
c.1400, from Old French stiptique, from Latin stypticus "astringent," from Greek styptikos, from styphein "to constrict, draw together." Spelling influenced by Latin and Greek words.
styptic styp·tic (stĭp'tĭk)
Contracting the tissues or blood vessels; astringent.
Tending to check bleeding by contracting the tissues or blood vessels; hemostatic.