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: 
"Damage Per Second". DPS refers to heroes whose main purpose is dealing damage. This (generally) means offense characters. Alternatively, it is the ability to put a lot of damage on a single target, allowing for quick picks. 

(Example) In Overwatch, a pharah can dish out insane DPS due to splash damage, no fall off on her rockets and her ability to focus on targets other team members can't. Meanwhile, a hero like Mei does significantly less DPS.
Damage
Per
Second

Yes, you are using it correctly.