cosmogony vs cosmogeny

cosmogony and cosmogeny both are nouns.

Word	Noun	Adjective	Verb	Adverb
cosmogony	Yes	No	No	No
cosmogeny	Yes	No	No	No

As nouns, cosmogony and cosmogeny are synonyms defined as:

cosmogony and cosmogeny: the branch of astrophysics that studies the origin and evolution and structure of the universe

Other synonyms of cosmogony include cosmology.

cosmogony (noun)	cosmogeny (noun)
the branch of astrophysics that studies the origin and evolution and structure of the universe	the branch of astrophysics that studies the origin and evolution and structure of the universe