ingress vs penetration

ingress and penetration both are nouns.

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

As nouns, penetration is a hyponym of ingress; that is, penetration is a word with a more specific, narrower meaning than ingress:

ingress (noun)	penetration (noun)
the act of entering	an attack that penetrates into enemy territory
(astronomy) the disappearance of a celestial body prior to an eclipse	the act of entering into or through something
	the act (by a man) of inserting his penis into the vagina of a woman
	the depth to which something penetrates (especially the depth reached by a projectile that hits a target)
	the ability to make way into or through something
	clear or deep perception of a situation