Have you ever watched a tennis match? If you're not familiar with the special scoring system used in tennis, you may have been really confused. Let's take a closer look at exactly how tennis players figure out who's winning.

Players take turns serving, which means hitting the ball first. The person who serves is called the "server." The other player is the "receiver." The receiver tries to return the ball to the server.

The play goes back and forth over the net until someone fails to return the ball. When that happens, the other player scores a point.

A tennis match consists of points, games, and sets. A player wins the match by winning the most sets. Men usually play matches that are best-of-five format (need to win three sets), while women usually play best-of-three format (need to win two sets).

A typical set consists of six games. Each game is made up of points. The first player to score four points — and have at least two points more than the other player — wins.

Scores for a game are given before each serve, with the serving player's score announced first followed by the receiving player's score. A game starts out at zero to zero — or as tennis players say, “love-love." In tennis, a score of zero is called “love."

Love isn't the only unique thing about tennis scoring, though. The first point won is called 15, the second point is 30, the third point is 40, and the fourth point is "game." Kind of strange, right?

So, if a serving player wins four straight points to win the game, the scores announced along the way would be: 15-love, 30-love, 40-love, and game. Of course, many other combinations of scores could occur along the way.

Since a player has to score four points and win by at least two points, what happens if both players score four points in a game? In that case, the score is 40-40 (or “40-all"), which is also called “deuce."

At deuce, the point system takes another interesting turn to the advantage system. At deuce, the next player to score a point is said to have “advantage." If that player then scores the next point, the game is won. If the other player scores, it goes back to deuce. This cycle will repeat until someone wins two points in a row to win the game.

No one knows for sure how the unique tennis scoring terminology came about, but some believe it came from medieval France, where clocks may have been used to keep score. Since four points are needed to win a game, a clock hand could be turned a quarter move — to 15, 30, 45, and 60 (back to 0) — to keep track of the score.

To allow for the special circumstances of deuce and advantage, people speculate that 45 was changed to 40. In this way, advantage could be marked by 50. If a game was won on the next point, the clock would be turned to 60 (back to 0) to signal the end of a game. If not, it could be turned back to 40 to signal a return to deuce.

As for love…well, that's a mystery. No definite explanation exists for the use of “love" to mean zero in tennis.

Some believe it comes from the French expression l'œuf (“the egg") since an egg looks like a zero. The more popular belief, though, is that love came about from the idea of playing simply for the love of the game or, in other words, for nothing or zero money.