The Collaborative International Dictionary
Tophus \To"phus\, n.; pl. Tophi. [NL.: cf. F. tophus a mineral concretion in the joint. See Toph.] [Written also tofus.]
(Med.) 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.
(Min.) Calcareous tufa.
n. (plural of tophus English)