Damage Per Second

DPS or Damage Per Second is generally considered an MMO term, which describes how much damage a character, spell, skill, ability or item can produce on average per second.

DPS Class

The class or monsters that deal damage are generally called "DPS" as an archtype in RPGs and ARPGs. How they deal damage is different.

The term is also often associated with "squishy" characters, who are essentially glass cannons - dealing massive damage, but are also easily killed.

Classes

The term DPS is used in Diablo 3 by the design team, when they stress the fact that (as was the case in Diablo II) all classes are capable of fighting and succeeding alone or in a party. In other words, there are no healers or tanks or casters who can only do one thing, and aren't capable of surviving or thriving on their own - all Diablo game classes are DPS classes.

On Items

DPS will show on the individual weapons in Diablo III, which some players like and others dislike.