jacket vs bed jacket

jacket and bed jacket both are nouns.

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

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

jacket: a short coat
bed jacket: a lightweight jacket worn over bedclothes (as when sitting in bed)

jacket (noun)	bed jacket (noun)
a short coat	a lightweight jacket worn over bedclothes (as when sitting in bed)
an outer wrapping or casing
(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

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