The set of functions F(x) + C, where C is any real number, such that F(x) is the integral of f(x) WordNet 3.0 & Open English WordNet

In calculus, an antiderivative, inverse derivative, primitive function, primitive integral or indefinite integral of a function f is a differentiable function F whose derivative is equal to the original function f. Wikipedia

Function whose derivative is the original function Wikidata

A numerical measure computed by a limiting process in which the domain of a function is divided into small subintervals and the value of the function at a point in each subinterval is multiplied by the measurement of that subinterval, all these products then being summed. OmegaWiki

A function whose derivative is a given function; an indefinite integral. Wiktionary

Function whose derivative is a given function. Wiktionary (translation)

A function whose derivative is a given function; an antiderivative. Wiktionary

Antiderivative. Wiktionary (translation)