Target

From WoWWiki

In World of Warcraft, a target can mean a few things:

1. Any selected mob or player.
2. A point on the ground used as a center reference for an Area of Effect attack.
3. A type of target dummy.
4. An in-game object that you usually can't interact with (but NPCs sometimes will) used for shooting at like a circular target for archery or a target dummy for melee combat practice.

Some units, usually NPCs, cannot be targeted. Thus, they cannot be the object of any action that requires a target, even area of effect spells.