proliferation vs ontogeny

proliferation and ontogeny both are nouns.

Word	Noun	Adjective	Verb	Adverb
proliferation	Yes	No	No	No
ontogeny	Yes	No	No	No

As nouns, ontogeny is a hypernym of proliferation; that is, ontogeny is a word with a broader meaning than proliferation:

proliferation: growth by the rapid multiplication of parts
ontogeny: (biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level

Other hypernyms of proliferation include development, growing, growth, maturation, ontogenesis.

proliferation (noun)	ontogeny (noun)
growth by the rapid multiplication of parts	(biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level
a rapid increase in number (especially a rapid increase in the number of deadly weapons)