keloid vs scar

keloid and scar both are nouns.

Word	Noun	Adjective	Verb	Adverb
keloid	Yes	No	No	No
scar	Yes	No	Yes	No

As nouns, scar is a hypernym of keloid; that is, scar is a word with a broader meaning than keloid:

keloid: raised pinkish scar tissue at the site of an injury; results from excessive tissue repair
scar: a mark left (usually on the skin) by the healing of injured tissue

Other hypernyms of keloid include cicatrice, cicatrix.

keloid (noun)	scar (noun)
raised pinkish scar tissue at the site of an injury; results from excessive tissue repair	an indication of damage
	a mark left (usually on the skin) by the healing of injured tissue

keloid (verb)	scar (verb)
	mark with a scar