What's the "een" in Halloween?
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.