It's been at least 6 years since 'DPS' has replaced 'DD' or 'attacker'.

It became that way due to chat. It evolved from, "So what's your dps," I believe. It also describes how raids view attackers. They are there for the amount of damage they can do in a given amount of time. Even a healer can do a thousand* points of damage eventually, but probably not in 30 seconds.


*An illustrative number, not to be taken too seriously.