“Smooth curve” redirects here. For the equivalent concept in algebraic geometry, see singular point of an algebraic variety.
“C infinity” redirects here. For the extended complex plane {displaystyle mathbb {C} _{infty }} {displaystyle mathbb {C} _{infty }}, see Riemann sphere.
For smoothness in number theory, see smooth number.

A bump function is a smooth function with compact support.
In mathematical analysis, the smoothness of a function is a property measured by the number of derivatives it has that are continuous. A smooth function is a function that has derivatives of all orders everywhere in its domain.