A tennis ball is a hollow rubber ball that is used primarily in tennis but is used in other ways. It is usually spherical, light (in weight), brightly coloured and has 2 white curved shapes as part of the design.
Even though, as the name suggests, the ball is used primarily in tennis, it can be used as a safe substitute for games where a solid ball is necessary, for example, to replace a cricket ball, which can inflict damage or injury if not used correctly.