egress vs emission

egress and emission both are nouns.

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

As nouns, emission is a hyponym of egress; that is, emission is a word with a more specific, narrower meaning than egress:

Other hyponyms of egress include surfacing, emanation.

egress (noun)	emission (noun)
the act of coming (or going) out; becoming apparent	the act of emitting; causing to flow forth
(astronomy) the reappearance of a celestial body after an eclipse	the occurrence of a flow of water (as from a pipe)
the becoming visible	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

egress (verb)	emission (verb)
come out of