periapsis vs point of periapsis

periapsis and point of periapsis both are nouns.

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

As nouns, periapsis and point of periapsis are synonyms defined as:

periapsis and point of periapsis: (astronomy) the point in an orbit closest to the body being orbited

periapsis (noun)	point of periapsis (noun)
(astronomy) the point in an orbit closest to the body being orbited	(astronomy) the point in an orbit closest to the body being orbited