Love? 15-30...40? What's the deal with tennis scoring? There’s no shortage of theories. Here are a few of them, along with input from sportscaster and former tennis pro Mary Carillo (pictured above with Rafael Nadal after his win in last night's U.S. Open men's final).

Love

You know how sometimes when a team in any sport comes up empty-handed on points, it’s said that there was a big ol’ goose egg on the scoreboard? Some people believe that a similar French expression is the reason zero points is called “love” in tennis. L’oeuf is French for “egg,” you see, so the thought is that over the years, we’ve slowly butchered the pronunciation into “love.”

Carillo agrees: “It’s the goose egg, exactly. Most tennis historians believe the French translation of ‘egg’ is probably the most likely theory.”

There's a less popular theory that we’ve managed to twist the Dutch or Flemish word “lof,” meaning “honor.” The idea is that the player with zero points is simply playing for honor—because he or she certainly isn’t playing for a win. But that’s not all the Dutch have up their sleeves: one more possibility stems from the lof in the phrase “iets voor lof doen,” which means to do something for praise.

The Oxford English Dictionary suggests that love really does mean “love.” The only thing keeping a scoreless player on the court is the love of the game.

A final “love” theory that doesn’t involve any kind of mistranslation or mispronunciation at all: When both players start at zero points and no one is winning or losing, they still have love for each other.

The 15-30-40 scoring

Now that “love” is as clear as mud, let’s figure out why tennis is scored in what appears to be a completely random jumble of numbers. Before there was tennis, there was a French game called jeu de paume (“palm game”) that was very similar to tennis, but players used their hands instead of a racquet. The scoring system we use for tennis today was based on jeu de paume’s system, but the reason for that 15-30-40-Game scoring is still a little shaky. There are three possibilities. First is the theory that, back in the pre-Revolution days, the 1000-plus jeu de paume courts in French were 90 feet total, 45 per side. Upon scoring, the server got to move up 15 feet. Another score meant another 15-foot scoot forward. Since a third score would put the server right at the net, 10 feet was the last bump forward.

If you’ve ever noticed the scoring system’s similarity to a clock face, you’re not alone. “That’s the theory I think is most common—that you’re just playing your way around the clock,” Carillo said. It makes even more sense when you know that in medieval numerology, the number 60 was considered a nice, round number, the way 100 is a satisfying set of digits today.

Finally, the Europeans were preoccupied with astronomy and sextant (one-sixth of a circle), which is 60 degrees, so they may have scored the game around the completion of a perfect circle. From the United States Tennis Association Official Encyclopedia of Tennis:

"In early records of the game in France, sets were played to four games. Since sixty degrees make a full circle when multiplied by six, it is thought that matches were six sets of four games each. Therefore, each point was worth fifteen degrees, or points, contributing to the whole. The game concluded when one player completed a full circle of 360 degrees."

Whichever one of these is the correct answer, it’s generally agreed that scoring used to be exactly what any logical person thinks it should be: 15, 30, 45, 60 (game). Over time, we’ve adapted 45 to 40 because it’s more clearly understood when yelled out on a court; “forty” can’t be confused with any other number.

Seinfeld's Theory

One of Carillo’s favorite scoring theories is not one you’ll find in history books. “I actually love the Seinfeld scoring system,” she told us. In typical Jerry Seinfeld fashion, he speculates that the points are awarded simply because playing tennis is just so damn hot:

Whatever the real reasons for the scoring system are, one thing's for certain: Tennis wouldn’t be tennis without the unique point tally. “I happen to love the scoring system,” Carillo said. “Because of it, you have games like the one that was won in 21 minutes [on Saturday], when Novak Djokovic won the semifinal against Stanislas Wawrinka. It was thrilling, it was absolutely thrilling. There was a standing ovation. As weird as the scoring system is, it just creates great tension and tactics in every game.”