Inequality: A mathematical statement that compares two values using symbols such as <, >, ≤ (less than or equal to), or ≥ (greater than or equal to).
Range: The set of all possible values of a function or variable. In this case, it defines the valid y-values for which we want to find the area enclosed.
Euler's Number (e): A special mathematical constant approximately equal to 2.71828. It serves as an upper bound in this inequality expression.