Meaning of CHAIN RULE in English

CHAIN RULE

noun Date: circa 1937 a mathematical rule concerning the differentiation of a function of a function (as f [ u ( x )]) by which under suitable conditions of continuity and differentiability one function is differentiated with respect to the second function considered as an independent variable and then the second function is differentiated with respect to its independent variable

Merriam Webster. Explanatory English dictionary Merriam Webster.      Толковый словарь английского языка Мерриам-Уэбстер.