astronomy vs celestial longitude

astronomy and celestial longitude both are nouns.

Word	Noun	Adjective	Verb	Adverb
astronomy	Yes	No	No	No
celestial longitude	Yes	No	No	No

astronomy (noun)	celestial longitude (noun)
the branch of physics that studies celestial bodies and the universe as a whole	(astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky; usually expressed in hours and minutes and seconds; used with declination to specify positions on the celestial sphere