Why is football called soccer in the US?
It is originally a British name. “Assoccer” (association football) was later shortened to “soccer”. The American football is called rugby football. Later British changes the name to football due to anti-americanism. But in America, football is named as a more popular sports like rugby football. So now it cannot change the name as the world called.
Instruction: Why is football called soccer in the US?
Context: 
Response: It is originally a British name. “Assoccer” (association football) was later shortened to “soccer”. The American football is called rugby football. Later British changes the name to football due to anti-americanism. But in America, football is named as a more popular sports like rugby football. So now it cannot change the name as the world called.