One word that always throws me out of a story is "sneakers". I know that this is an American term, but every time I see it, no matter where the story is taking place, I always have to pause and remind myself "That word means 'runners'. As in running shoes."
Also, the "freshman/sophomore/junior/senior" thing confuses me. I always have to go through the whole list and convert it to number values before I can understand it.
