Tennis is a sport that involves two or four players hitting a ball over a net with rackets. The term 'ALL' is used when both players have scored the same number of points, 'LET' is when a point is replayed due to a disturbance, 'SET' is a group of games played to determine the winner of a match, 'DEUCE' is when both players have scored 40 points, 'LOVE' is when a player has no points, 'LOB' is a shot hit high and deep over the opponent's head, 'ADIN' is an advantage point after DEUCE, 'SERVE' is a shot to start a point, 'LOVESET' is when a player wins a SET without losing a game, 'FOOTFAULT' is when a player steps on the baseline while serving, and 'MATCHPOINT' is when a player needs one more point to win the match.