Glossary of Tennis Terms - U

U

• underspin: Spin of a ball where the top of the ball rotates away from the direction of travel; the spin is underneath the ball, causing the ball to float and to bounce at a lower angle to the court.
• umpire: Person designated to enforce the rules of the game during play, usually sitting on a high chair beside the net.
• underhand service (serve): Service in which the player serving delivers the ball with his or her racquet below shoulder level. In intermediate level tennis this is considered unusual but an acceptable ploy. In upper-intermediate and professional events, the practice would generally be considered insulting, but there may be exceptions (for example, if the server is injured).
• unforced error: Error in a service or return shot that cannot be attributed to any factor other than poor judgement and execution by the player; contrasted with forced error.
• unseeded player: Player who is not a seed in a tournament.