periapsis vs celestial point

periapsis and celestial point both are nouns.

Word	Noun	Adjective	Verb	Adverb
periapsis	Yes	No	No	No
celestial point	Yes	No	No	No

As nouns, celestial point is a hypernym of periapsis; that is, celestial point is a word with a broader meaning than periapsis:

periapsis: (astronomy) the point in an orbit closest to the body being orbited
celestial point: a point in the heavens (on the celestial sphere)

periapsis (noun)	celestial point (noun)
(astronomy) the point in an orbit closest to the body being orbited	a point in the heavens (on the celestial sphere)