immersion vs ingress

immersion and ingress both are nouns.

Word	Noun	Adjective	Verb	Adverb
immersion	Yes	No	No	No
ingress	Yes	No	No	No

As nouns, immersion and ingress are synonyms defined as:

immersion and ingress: (astronomy) the disappearance of a celestial body prior to an eclipse

immersion (noun)	ingress (noun)
a form of baptism in which part or all of a person's body is submerged	the act of entering
the act of wetting something by submerging it	(astronomy) the disappearance of a celestial body prior to an eclipse
complete attention; intense mental effort
sinking until covered completely with water
(astronomy) the disappearance of a celestial body prior to an eclipse