celestial sphere vs solar apex

celestial sphere and solar apex both are nouns.

Word	Noun	Adjective	Verb	Adverb
celestial sphere	Yes	No	No	No
solar apex	Yes	No	No	No

celestial sphere (noun)	solar apex (noun)
the apparent surface of the imaginary sphere on which celestial bodies appear to be projected	the point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars