Pull

This term means to carefully approaching a large group of mobs with intent of aggroing only a small amount of them, preferrably one.

In Guild Wars, enemies have a tendancy to cluster together in large groups that can quickly overwhelm even a powerful, experienced party with their superior numbers. By judicious use of the aggro bubble, an experienced puller can draw a small number of enemies away from the rest, towards his/her party waiting a short distance away, making for a much more managable fight.

Pulling can be more difficult against certain mob groups such as Hydras or Minotaurs, which tend to move quickly and erratically.