If you watch much soccer, you've probably heard a lot of people call the sport "football." That's the most popular name for the planet's most popular sport. It makes sense: Players kick the ball with their feet. Why call it anything else?

If you're American, however, there's a good chance you call it "soccer." And despite what British fans may tell you, there's a good reason you call it that. They should know — soccer is a British word.

The word "soccer" dates back to the 19th-century birth of modern football, when the proto-sport was still evolving and splintering. It has a more precise meaning than the broader term "football," points out University of Michigan professor Stefan Szymanski in a recent paper, since it was coined to distinguish association football from other versions of the sport, like rugby football and Gaelic football. "Soccer" is just old British slang for "association," but that hasn't saved it from being lambasted by modern football fans — including the British — as a crude American colloquialism.

"I wince every time I hear the word 'soccer,'" one blogger wrote after the 2010 World Cup. "It makes my beloved sport football sound so alien, so uncouth, almost like someone just swore at me." Similar sentiments abound online, Szymanski notes, like this one from Bleacher Report: "It seems that almost every American can't understand that there is no sport called soccer .... its FOOTBALL!"

"These people have conveniently forgotten, or they don't realize, that the word soccer originated in England," Szymanski writes in a press release. "It was only later adopted by Americans to distinguish it from gridiron." But how exactly did the word "soccer" come to be? And why did Americans end up using it while Britain and most other countries settled on just "football"?

cuju Children play cuju in a painting by 12th-century Chinese artist Su Hanchen. (Image: Wikimedia Commons)

The birth of football

People have been playing football-like sports for centuries, from the ancient Chinese cuju (pictured above) to the Mayan game pok ta pok, which used a rubber ball. Yet football as it's played in the World Cup or the Olympics was born more recently in Britain. A variety of forms grew across the British Isles from the 8th to 19th centuries, according to FIFA, including a village-scale melee called "mob football."

By the early 1800s, a more regulated type of football was becoming popular among aristocratic boys in England's top schools, such as Eton, Harrow and Rugby. Each school developed its own version of the game, according to Szymanski, but the desire to play other schools required some standardization. The first formal rules were written in Cambridge in 1848, and the Football Association was founded 15 years later in London to promote a standardized game based on Cambridge rules.

This led to a schism in the sport that still echoes today. Some types of football had long involved use of the hands — "football" originally meant an array of ball games played on foot rather than horseback, and didn't necessarily refer to kicking. By the 1800s the Rugby School had become most famous for this hands-on style of play. In 1871, a group of clubs met in London to form the Rugby Football Union, and from then on the two versions of football were distinguished as Rugby Football and Association Football. The latter is a mouthful, especially compared to "rugby," so it clearly needed a nickname.

But how did "association" become "soccer"? For one, it was common at the time in England to form slang by adding -er, like "rugger" from Rugby. Plus, as the Online Etymology Dictionary points out, "those who did it perhaps shied away from making a name out of the first three letters of Assoc."

Royal Engineers A.F.C. The Royal Engineers, who played in England's first Football Association Cup Finals in 1872. (Photo: Wikimedia Commons)

The name game

Early American football was similarly nebulous, with wide-ranging rules that evolved quickly, sometimes during games. Harvard students in the 1870s played a style called the Boston game, which was soccer-like but let players carry the ball under certain circumstances. McGill University in Canada played a more rugby-like sport with an oval ball, and in 1874 the two schools played the first match of what would become modern American football. Borrowing parts of the Canadian game, such as downs and tackling, Harvard imported the new sport to its rivalry with Yale. (Canada is one of several countries where association football is still widely known as soccer.)

The popularity of this football required another name for association football, so Americans used the British nickname "soccer." This was still a recognized term at the time in England, Szymanski says, but it wasn't used widely in publications until after World War II. It then peaked in popularity among the British from 1960 to 1980, when soccer and football were used almost interchangeably.

It's unclear why "soccer" grew more common in Britain after World War II, although Szymanski suggests it may have been due to changing formality norms and the popularity of U.S. soldiers stationed there. That same association with America, however, seems to have had the opposite effect a few decades later. "In the 1980s you start to hear the argument that soccer is an American word, as distinct from the British football," Szymanski says. "It is hard to think of any explanation for the decline [of 'soccer' in England] other than the rising popularity of the word soccer in the U.S."

Anfield football stadium, Liverpool, England Fog covers the field at Anfield football stadium in Liverpool, England. (Photo: Andrew Yates/AFP/Getty Images)

Yet both words remain useful for different purposes. Soccer is a type of football, as are rugby and American football. Since association football is the most popular version on Earth, it makes sense for most people to call it "football" without specifying the type. But in places where other kinds of football are more popular, it makes sense to specify association football — and to use a shorter word for it. Plus, Szymanski says, there's no reason "the beautiful game" can't have multiple names.

"Americans will continue to call the game soccer whatever anyone else says, not out of perversity but out of the need to distinguish it from America's favorite game, football," he says. "The rest of us can continue to get mad about it if we want, but it might be more sensible to get over it and recognize that our favorite game can just as easily be called soccer as football."

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.

Why it's OK to say 'soccer' instead of 'football'
Some football fans mock 'soccer' as crude U.S. slang, but it's a 120-year-old British word that's actually more specific.