What is the outer part of a tennis racquet handle called?

The grip of a tennis racquet is the outer covering of a racquet’s handle, which provides a cushioned surface to protect a player’s hand from the harsh surface of the handle, while also providing traction that ensures a firm grip to prevent the racquet from slipping. If needed, you can swap out the original grip with a replacement grip or wrap an overgrip on top of the stock grip for extra traction and sweat absorption.

Source: Tennis Companion