What does Boxing Day have to do with boxing?
"downy surface of cloth," mid-15c., from Middle Dutch or Middle Low German noppe "nap, tuft of wool," probably introduced by Flemish cloth-workers. Cognate with Old English hnoppian "to pluck," ahneopan "pluck off," Old Swedish niupa "to pinch," Gothic dis-hniupan "to tear."
"short spell of sleep," c.1300, from nap (v.). With take (v.) from c.1400.
Old English hnappian "to doze, sleep lightly," of unknown origin, apparently related to Old High German hnaffezan, German dialectal nafzen, Norwegian napp. Related: Napped; napping.
"to furnish with a nap, raise the nap of," 1610s, from nap (n.1).