doorjamb vs jamb

doorjamb and jamb both are nouns.

Word	Noun	Adjective	Verb	Adverb
doorjamb	Yes	No	No	No
jamb	Yes	No	No	No

As nouns, jamb is a hypernym of doorjamb; that is, jamb is a word with a broader meaning than doorjamb:

doorjamb: a jamb for a door
jamb: upright consisting of a vertical side member of a door or window frame

doorjamb (noun)	jamb (noun)
a jamb for a door	upright consisting of a vertical side member of a door or window frame