jacket vs casing

jacket and casing both are nouns.

Word	Noun	Adjective	Verb	Adverb
jacket	Yes	No	Yes	No
casing	Yes	No	No	No

As nouns, casing is a hypernym of jacket; that is, casing is a word with a broader meaning than jacket:

Other hypernyms of jacket include case, shell.

jacket (noun)	casing (noun)
a short coat	the enclosing frame around a door or window opening
an outer wrapping or casing	the housing or outer covering of something
(dentistry) dental appliance consisting of an artificial crown for a broken or decayed tooth	the outermost covering of a pneumatic tire
the tough metal shell casing for certain kinds of ammunition
the outer skin of a potato

jacket (verb)	casing (verb)
put a jacket on
provide with a thermally non-conducting cover