papilledema vs oedema

papilledema and oedema both are nouns.

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

As nouns, oedema is a hypernym of papilledema; that is, oedema 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
oedema: swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities

Other hypernyms of papilledema include dropsy, edema, hydrops.

papilledema (noun)	oedema (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