breakthrough vs penetration

breakthrough and penetration both are nouns.

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

As nouns, penetration is a hypernym of breakthrough; that is, penetration is a word with a broader meaning than breakthrough:

Other hypernyms of breakthrough include incursion.

breakthrough (noun)	penetration (noun)
a penetration of a barrier such as an enemy's defense	an attack that penetrates into enemy territory
making an important discovery	the act of entering into or through something
a productive insight	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