What is "Sustained DPS"?

[Pells]

B-But there's never a lull period where you're regaining TP/MP (unless you're a BLM/DRK where MP management is your gimmick). TP should be a constant drain from start to finish. If it's not, your DPS is suffering, hard. The burst regen from Invigorate every 2m doesn't really count as a period of regaining TP.

As far as sustained dps goes, there is no finish. That is what I mean by 'indefinite period'. If you are running out of resources, you obviously can't sustain that level of dps.

When you have an end point that you can plan to run out of juice (the boss dies), then you're really dealing with encounter dps. While this is the more useful kind to deal with, it's not what was asked to be defined by the OP.