Oh yeah I realize Americans know what it means. I just think it's prettier for them because it's more of a word-word than a season-word. It's a novelty word in a way, I think kids would think of it as a special word for Fall. It's just a little less used in America than it is here. I can't seem to put this whole "Autumn" line of thought into words very well but I hope you get what I mean. =)