calculus vs tophus

calculus and tophus both are nouns.

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

As nouns, calculus and tophus are synonyms defined as:

Other synonyms of calculus include tartar.

calculus (noun)	tophus (noun)
the branch of mathematics that is concerned with limits and with the differentiation and integration of functions	an incrustation that forms on the teeth and gums
a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body	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