Target

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.

Friendly units are selected for beneficial or nominally benign actions. This is the same thing as targeting, and the terms are used interchangeably, although the implied intent is different.

Left clicking a PC, NPC, or mob will target it. Right clicking is used for more direct interaction; it selects and will open a dialog with a friendly NPC if the NPC has a dialog for you, but it will target and auto-attack a hostile NPC or a neutral or hostile mob if it is within range of your melee weapon(s), or if it is within range of your ranged weapon if you are playing a hunter and have autoshot turned on. The tab key also targets and selects, and macros can step through targeting/selection choices.

Many neutral or hostile units, usually NPCs, cannot be targeted. Thus, they cannot be the object of any action that requires a specific target. Area of effect spells generally will not work on these units either, but may be worth testing. Summoning a friendly combat mob to fight for you has sometimes worked around targeting restrictions.

Targeting a mount that is being ridden will target the player character, not the mount. The mount is in effect a rather large extension of the PC under the PC.

A targetable (or selectable) object (or unit) in front of another targetable (or selectable) object (or unit) will block the ability to target the further object. If it fully covers the other object, that object cannot be targeted by clicking on it. Units can still be targeted by using the tab key or macros.