tendonitis vs redness

tendonitis and redness both are nouns.

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

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

tendonitis: inflammation of a tendon
redness: a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat

Other hypernyms of tendonitis include inflammation, rubor.

tendonitis (noun)	redness (noun)
inflammation of a tendon	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