differentiability

This term is a technical abstraction used almost exclusively within the fields of calculus and mathematical analysis. It describes a specific structural quality of a function, indicating that the function does not have any sharp corners, jumps, or vertical tangents that would prevent the calculation of a derivative.

Because it refers to a mathematical property or state of being, it is treated as an uncountable noun. It is not used to describe a quantity of things, but rather the existence of a specific characteristic within a mathematical object.