A definite integral is a mathematical concept used to calculate the area under a curve defined by a function over a specific interval. It is represented as ∫[a, b] f(x) dx, where f(x) is the function, and a and b are the limits of integration. The result of a definite integral is a numerical value that represents this area. Definite integrals are fundamental in various fields, including physics and engineering, as they help in determining quantities like distance, area, and volume. They are closely related to the concept of the antiderivative, which is used to find the function that, when differentiated, gives the original function.