service ceiling vs ceiling

service ceiling and ceiling both are nouns.

Word	Noun	Adjective	Verb	Adverb
service ceiling	Yes	No	No	No
ceiling	Yes	No	No	No

As nouns, ceiling is a hypernym of service ceiling; that is, ceiling is a word with a broader meaning than service ceiling:

service ceiling: altitude above which a plane cannot climb faster than a given rate
ceiling: maximum altitude at which a plane can fly (under specified conditions)

service ceiling (noun)	ceiling (noun)
altitude above which a plane cannot climb faster than a given rate	the overhead upper surface of a covered space
	(meteorology) altitude of the lowest layer of clouds
	maximum altitude at which a plane can fly (under specified conditions)
	an upper limit on what is allowed