Kiting refers to keeping an enemy chasing you while also keeping it at a range where it cannot attack you. This tactic is often paired with attacking him backused to more safely attack the enemy using your owna long-range attack, but that is not necessary (see or to distract the comments below for an example)enemy while others attack it.
The effect looks like you have the enemy on the end of a string, kind of like a 'kite', because you are both moving in the same direction and he's never catching up to you. It is a generic term that applies to any game with mechanics that allow it.