Tophus
Tophus , noun
[New Latin: compare French tophus a mineral concretion in the joint. See Toph.]
1.
(Medicine) 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.
2.
(Mineralogy) Calcareous tufa.