ENCASING

Verb

encasing

present participle of encase

Noun

encasing (plural encasings)

That which encases; an outer cover.

Put two encasings on a mattress if one must be removed periodically for cleaning.

Source: Wiktionary

ENCASE

En*case", v. t. Etym: [Cf. Enchase.]

Definition: To inclose as in a case. See Incase. Beau. & Fl.

Source: Webster’s Unabridged Dictionary 1913 Edition