en·crus·ta·tion / ˌenkrəsˈtāshən/ (also in·crus·ta·tion) • n. the action of encrusting or state of being encrusted. ∎ a crust or hard coating on the surface of something: the sides are white with encrustations of salt. ∎ an outer layer or crust of ornamentation. ∎ Archit. a facing of marble on a building.