\To"phus\, n.; pl. {Tophi}. [NL.: cf. F. tophus a mineral
concretion in the joint. See {Toph}.] [Written also {tofus}.]
1. (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.
2. (Min.) Calcareous tufa.