If you wear A&F, AE, and Aeropostal you aren't a prep. This is a definition of Prep:
A true preppy is someone who:
Wears, but is not limited to, Polo, Lilly, Brooks Brothers, Lacoste, LL Bean (ie duck boots), ribbon belts, prints (ie cords with embroidered whales, palm trees, etc), sweaters tied around the neck, collar always popped, looks neat and put together. Hair ribbons or ribbon headbands, pearls, and other classic jewelry pull the look together. Preppies are partial to monogrammed and engraved items (ie tote bags, oxford shirts, jewelry, money clips, etc). Colors are always brite (favorites include pink and lime green). Preppies may not always match EXACTLY but they are always coordinated. Hats are worn (ie polo player, Lacoste, Brooks Brothers), but they are unique- not designs you would see in the mainstream and the "mall".
Preppies often attend prep schools (ie Middlesex School, Governor Dummer Academy, and Belmont Hill) followed by New England private colleges.
They are confident and unafraid to express their own styles and be daring in their fashions. Preppies vacation on Nantucket, Martha's Vineyard, Delray Beach, and on the coast of Maine. These vacation locales are places their families have been going to for years, and have histories there.
It is a common misconception that preppies are snobs. Many people view them as unapproachable, and as a result mislabel them. Preppies are not as rich as people may think they are, but they are often well off. They buy into classics rather than trends, and don't change their lifestyles with fads.
Preppies tend to have bizarre connections with other preppies they meet, always finding mutual friends/ family and people that run in the same circle.
Preppies don't:
* Wear tight, skin exposing clothing (ie fitted Abercrombie sexual tshirts with tight flared jeans)
* Limit themselves to mall shopping and chain stores. They gravitate towards long-established classic stores and boutiques unique to quaint New England towns.
* Wear heavy makeup and endless hair products. The phrase "less is more" is a preppy creed.
* Glue purses to their arms, especially when going to school. Lip gloss and if need be, a wallet, are thrown into tote bags along with books.
That is what a true prep is.
Now on for me,
I make good grades so I must be a nerd.
Rockin the big V! 
