what is a prep?

I was at the place I get my hair done today and the lady cutting my hair and I started talking about what is a prep? what makes a person a prep and what does this word really mean? so I told her that I would ask as many people as I can and this is one way to see what ya'll think... so if you would tell me what you think makes a person a 'prep' ?

A prep is a person whom wears tendy clothes and is not a jock, geek, greaser, goth or stoner. They would be the people that have good grades and normally are rich.