What does Boxing Day have to do with boxing?
also encrustation, 1640s, from Late Latin incrustationem (nominative incrustatio) "a covering with crust," noun of action from past participle stem of incrustare.
incrustation in·crust·a·tion (ĭn'krŭ-stā'shən)
The formation of a crust or a scab.
A coating of hardened exudate or other material on a body or body part.