American football became known as "football" after evolving from the game of "rugby football." Rule changes prohibiting the use of hands in the sport of "soccer" led to the creation of "rugby football."
The split came in 1863 when the Football Association formed to promote the "no hands" game, known as "association football" to distinguish it from rugby. It is unclear why the creators of American football opted not to include the "rugby" name.
In the early 1900s, "association football" became known as "soccer" in America. While the term originated in Europe, it is now primarily used only in the United States and Canada.