chalkstone vs tophus

chalkstone and tophus both are nouns.

Word	Noun	Adjective	Verb	Adverb
chalkstone	Yes	No	No	No
tophus	Yes	No	No	No

As nouns, chalkstone and tophus are synonyms defined as:

chalkstone and tophus: a deposit of urates around a joint or in the external ear; diagnostic of advanced or chronic gout

chalkstone (noun)	tophus (noun)
a deposit of urates around a joint or in the external ear; diagnostic of advanced or chronic gout	an incrustation that forms on the teeth and gums
	a deposit of urates around a joint or in the external ear; diagnostic of advanced or chronic gout