PvP or player versus player is one of the game modes that takes place in an area called The Crucible. In The Crucible players will battle against other players in 6 different PvP modes. Players will earn various rewards such as experience points, gear and reputation by participating in PvP.
In PvP the players' stats are normalized, the player's level advantage, Attack of your weapons and the Defense of your armor do not matter. Other weapons stats such as Impact, armor stats such as Discipline and sublcass stats do matter.