Jamie Squire/Getty Images
The word "soccer" is a British invention that British people only stopped using about 30 years ago, according to a new paper by University of Michigan professor Stefan Szymanski.
The word "soccer" comes from the use of the term "association football" in Britain, and it goes back 200 years.
In the early-1800s a bunch of British universities took "football" - a medieval game - and started playing their own versions of it, all under different rules. To standardized things across the country, these games were categorized under different organizations with different names.
One variant of the game you played with your hands became "rugby football." Another variant came to be known as "association football" after the Football Association formed to promote the game in 1863, 15 years after the rules were made at Cambridge.
"Rugby football" became "ruggle" for short. "Association football" became "soccer."
After these two sports spread across the Atlantic, Americans invented their own variant of the game that they simply called "football" in the early 1900s.
"Association football" became "soccer" in America, and what was called "gridiron" in Britain became simply "football" in America.
The interesting thing here is that Brits still used "soccer" regularly for a huge chunk of the 20th century. Between 1960 and 1980, "soccer" and "football" were "almost interchangeable" in Britain, Szymanski found.
Then everything changed (via Szymanski):
"Since 1980 the usage of the word 'soccer' has declined in British publications, and where it is used, it usually refers to an American context. This decline seems to be a reaction against the increased usage in the US which seems to be associated with the highpoint of the NASL around 1980."
British people stopped saying "soccer" because of its American connotations.
So no, it's not wrong to call it "soccer" if you're American.