ejaculation vs emission

ejaculation and emission both are nouns.

Word	Noun	Adjective	Verb	Adverb
ejaculation	Yes	No	No	No
emission	Yes	No	No	No

As nouns, emission is a hypernym of ejaculation; that is, emission is a word with a broader meaning than ejaculation:

ejaculation: the discharge of semen in males
emission: any of several bodily processes by which substances go out of the body

Other hypernyms of ejaculation include discharge, expelling.

ejaculation (noun)	emission (noun)
an abrupt emphatic exclamation expressing emotion	the act of emitting; causing to flow forth
the discharge of semen in males	the occurrence of a flow of water (as from a pipe)
	the release of electrons from parent atoms
	any of several bodily processes by which substances go out of the body
	a substance that is emitted or released