What is a 55 build?

I hear alot about 55 builds with warriors but what exactly are they? I havent bought the game yet but I'm spending some time to review builds. What are its strengths, weaknesses?

If you want to review builds, go to the builds forum. 55 monks, often called solo monks or invincimonks, are what you want to look for. There are sometimes variants made for Mesmers and Necros too. Otherwise, closed as this question gets asked too often.