Tennis is a sport where players use rackets to hit a ball back and forth over a net, trying to make shots their opponent can't return. You can play singles (one against one) or doubles (two against two) on a rectangular court.

The game has an unusual scoring system: points go 15, 30, 40, then game. If both players reach 40 (called deuce), someone must win two points in a row to take the game. Players switch sides of the court after odd-numbered games, and matches are won by winning multiple sets.

Tennis began in France during the Middle Ages but became the modern sport we know in England during the 1870s. Today it's played worldwide, from local parks to professional tournaments like Wimbledon and the US Open. The sport demands quick reflexes, strategic thinking, and stamina. Players might run several miles during a single match, constantly adjusting their position and planning their next shot.

A tennis ball is the fuzzy yellow ball used in the game. The word also appears in table tennis, the formal name for ping-pong, which follows similar rules but uses a much smaller table, ball, and paddle.