casing vs jacket

casing and jacket both are nouns.

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

As nouns, jacket is a hyponym of casing; that is, jacket is a word with a more specific, narrower meaning than casing:

Other hyponyms of casing include boot, gear box, gear case, gearbox.

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

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