It’s not an Americanism:

“Soccer,” by the way, is not some Yankee neologism but a word of impeccably British origin. It owes its coinage to a domestic rival, rugby, whose proponents were fighting a losing battle over the football brand around the time that we were preoccupied with a more sanguinary civil war. Rugby’s nickname was (and is) rugger, and its players are called ruggers-a bit of upper-class twittery, as in “champers,” for champagne, or “preggers,” for enceinte. “Soccer” is rugger’s equivalent in Oxbridge-speak. The “soc” part is short for “assoc,” which is short for “association,” as in “association football,” the rules of which were codified in 1863 by the all-powerful Football Association, or FA-the FA being to the U.K. what the NFL, the NBA, and MLB are to the U.S.