a hard stony mass, e.g. of cholesterol, that forms abnormally in the kidney, gall bladder, or other hollow organ or tube, may cause a painful blockage, and often requires removal by a surgical operation

tartar that accumulates on the teeth

a branch of mathematics, comprising differential and integral calculus, that deals with rates of change of functions and the ideas of limits and has applications to the calculation of arcs, areas, volumes, etc

any system of calculation that uses a special symbolic notation