breakthrough vs discovery

breakthrough and discovery both are nouns.

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

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

Other hypernyms of breakthrough include find, uncovering.

As nouns, breakthrough and discovery are synonyms defined as:

Other synonyms of breakthrough include find.

breakthrough (noun)	discovery (noun)
a penetration of a barrier such as an enemy's defense	the act of discovering something
making an important discovery	a productive insight
a productive insight	something that is discovered
	(law) compulsory pretrial disclosure of documents relevant to a case; enables one side in a litigation to elicit information from the other side concerning the facts in the case