noun (n)

• a deposit of urates around a joint or in the external ear; diagnostic of advanced or chronic gout(noun.substance)

  Synonym:
  chalkstone
  

  source: wordnet30
• an incrustation that forms on the teeth and gums(noun.object)

  Synonym:
  calculus, tartar
  

  source: wordnet30
• One of the mineral concretions about the joints, and in other situations, occurring chiefly in gouty persons. They consist usually of urate of sodium; when occurring in the internal organs they are also composed of phosphate of calcium.(noun)

  source: webster1913