A tennis ball is a small, spherical object used in the sport of tennis. It is typically made of a rubber core covered with felt, usually in a bright yellow color for visibility on the court. The ball is designed to be lightweight and durable, with a consistent bounce that allows for fast-paced play. Tennis ball are pressurized to maintain their shape and bounce, and they come in different types suited for various playing surfaces, including grass, clay, and hard courts.