roof vs saddle roof

roof and saddle roof both are nouns.

Word	Noun	Adjective	Verb	Adverb
roof	Yes	No	Yes	No
saddle roof	Yes	No	No	No

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

roof (noun)	saddle roof (noun)
a protective covering that covers or forms the top of a building	a double sloping roof with a ridge and gables at each end
protective covering on top of a motor vehicle
an upper limit on what is allowed
the inner top surface of a covered area or hollow space

roof (verb)	saddle roof (verb)
provide a building with a roof; cover a building with a roof