Kiting refers to keeping an enemy chasing you while also keeping it at a range where it cannot attack you. This is often paired with attacking him back using your own long-range attack, but is not necessary (see the comments below for an example).

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.