Americans calls it soccer, but we europeans call it Soccer. And shatta is right, most of the american soccer you play it with the ball in you're hands, running towards the opposited team area, to score, and you trow the ball to you're team mates with the hands, while in Soccer only the goalkeeper can touch it with the hands.
Also in American soccer, a kickoff only occurs at the start of each half and before each overtime and after a touchdown or field goal.