The word pwn is a result of the internet gaming subculture. In the effort to increase their typing speeds, online gamers often accidentally typed “pwned” instead the desired “owned”, a term meaning to defeat and a celebration of victory. The idea was to say a phrase such as “I owned you”, but often the result would be “I pwned you” due to the proximity of the keys on a standard qwerty keyboard. More about the word can be found here.