papilledema vs hydrops

papilledema and hydrops both are nouns.

Word	Noun	Adjective	Verb	Adverb
papilledema	Yes	No	No	No
hydrops	Yes	No	No	No

As nouns, hydrops is a hypernym of papilledema; that is, hydrops is a word with a broader meaning than papilledema:

papilledema: swelling of the optic disc (where the optic nerve enters the eyeball); usually associated with an increase in intraocular pressure
hydrops: swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities

Other hypernyms of papilledema include dropsy, edema, oedema.

papilledema (noun)	hydrops (noun)
swelling of the optic disc (where the optic nerve enters the eyeball); usually associated with an increase in intraocular pressure	swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities