Tennis

1. a popular spectator sport - spectator sport –noun any sport that can be watched by spectators, as football or basketball, usually for a fee.
2. a felt-covered ball
3. to return a shot
   

   A player wins a point when his or her opponent cannot return a shot, or the opponent's shot doesn't land in the court.

4. 30-love
   

   Why does love mean zero?
   Love, meaning zero (in tennis only), comes from the French word 'l'oeuf', meaning egg, and was used because of an egg's round shape, the same as zero (0).

5. a grass, clay, or hard court tennis surface
6. the receiver
7. six games
   

   Play continues until a player wins the first 'set' by being the first to win at least six games.

8. different shots
   

   Professional players learn to use many different shots, including the serve, forehand, backhand, volley, half-volley, overhead smash, drop shot, and lob. They also learn how to put spin on their shots to make them more difficult to return, and learn how to use tactics to win, such as by playing to their opponent's weaknesses.

9. ace
   a winning serve which the receiver fails to touch with his or her racket
10. deuce
    Tennis. a situation, as a score of 40–40 in a game or 5–5 in a match, in which a player must score two successive points to win the game or two successive games to win the set.
11. advantage
    a player who scores a point at 'deuce' has the advantage, meaning if they win the next point, they win the game
    
    
    More at: http://www.englishclub.com/vocabulary/sports-tennis.htm