Meaning of CALCULUS in English

[] n, pl -li also [L, stone (used in reckoning)] (1666) 1 a: a method of computation or calculation in a special notation (as of logic or symbolic logic) b: the mathematical methods comprising differential and integral calculus

2: calculation 3 a: a concretion usu. of mineral salts around organic material found esp. in hollow organs or ducts b: tartar 2

4: a system or arrangement of intricate or interrelated parts

Merriam-Webster English vocab.      Английский словарь Merriam Webster.