Tween always struck me as pointing at that group of kids aged between 10 and thirteen, the 11 and 12 year olds. But you're right about early maturity, Helen, and it's more than just physical. I spent part of the afternoon yesterday trying not to laugh when an 11-year-old schoolfriend of my goddaughter decided to flirt with me. Batting eyelids, knowing looks, risque language, the works. This kid has only the hint of a bust and otherwise resembles a drain pipe, physically. But she's got the hype and the attitude all sorted for when her physical growth matches her attitude!