Tennis is a racket sport that is played either individually against a
single opponent (singles) or between two teams of two players each
(doubles). Each player uses a tennis racket strung with a cord to strike a
hollow rubber ball covered with felt over or around a net and into the
opponent's court. The object of the game is to manoeuvre the ball in such
a way that the opponent is not able to play a valid return. The player
unable to return the ball validly will not gain a point, while the
opposite player will.
