DPS

Damage per second (DPS or dps) is a measure of the damage dealt by a person or group over one second. DPS is a more practical measure of damage output than plain damage, as it allows characters of differing levels and classes to effectively compare their damage output.

The term dps is also sometimes used to describe the act of applying damage to a target (as in "all dps on the boss" or "stop all dps"), or to refer to a class whose primary role in a group is dealing damage, i.e. damage dealer.

Some players will be able to get an effective idea of DPS from getting their Hit Cap for bosses of their level. You can find out your Hit Cap by mousing over Hit Rating in your Character Stats Menu, which is to the right of your Character Info UI frame. For the easiest way to determine Hit Cap, use 17% for most DPS at Level 70 and above. This includes Caster and Ranged DPS. Your hit chance will drop as you level until you get gear that is your level with Hit Rating. At max level, getting Hit Rating will be much easier as you do not have to worry about the rating dropping

Burst DPS
"Burst DPS" refers to damage dealt over a relatively short period of time. High burst damage is the preferable form of damage against targets at/with relatively low health. Most classes have at least a few spells or abilities that generate high damage very quickly. This type of damage is preferred in PvP environments, but is usually too expensive or has too long a cooldown to be sustainable.

Sustained DPS
"Sustained DPS" refers to constant damage dealt over an extended period of time. High sustained damage is the preferable form of damage against targets with relatively high health. Every class is capable, when specced and geared properly, of doing good sustained damage. Zone Masters, Werewolves, Agents, and Fortians tend to have the highest sustained dps, as "pure" dps classes.
 * Note that Sustained DPS is best calculated on a one-boss encounter. Full raid / dungeon DPS calculates AOE damage into your DPS, greatly increasing it.