episcleritis vs redness

episcleritis and redness both are nouns.

Word	Noun	Adjective	Verb	Adverb
episcleritis	Yes	No	No	No
redness	Yes	No	No	No

As nouns, redness is a hypernym of episcleritis; that is, redness is a word with a broader meaning than episcleritis:

episcleritis: inflammation of the sclera of the eye
redness: a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat

Other hypernyms of episcleritis include inflammation, rubor.

episcleritis (noun)	redness (noun)
inflammation of the sclera of the eye	red color or pigment; the chromatic color resembling the hue of blood
	a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat