Question: I think it originates from MMORPGs, particularly World of Warcraft. I think it refers to more than one thing. Did it really originate from MMORPGs? Does it mean one thing exclusively, or can it mean something else ina different context?

What does the term DPS mean?

Answer: 
DPS means, simply, **D**amage **P**er **S**econd. It is a numerical value that represents the amount of damage one player can inflict onto another or the environment.

DPS is not dependent on class as much as it is loadout and abilities/skill - it can change drastically based on what weaponry you use.

It can be calculated by attacking a mob or similar non-stop for five seconds, and dividing the total HP lost by 5. Typically, the DPS stats you see in game are "optimal", meaning assuming you attack perfectly for one second.
DPS as a person: A dedicated damage dealer class and specialization, such as an Arms Warrior or Shadow Priest.

DPS as a measurement: The amount of damage done every second over a period of time (5 seconds, 1 minute, an entire boss fight). Typically seen in damage meters like Details.

**Examples of usage:**

*LF3DPS*: Looking for 3 damage dealers/ Need 3 dedicated damage dealers.

*Your DPS is low*: The rate of damage you're outputting is low