Are the ergosphere and accretion disk the same thing?

While accretion disks are found in more than just black holes, an ergosphere is the region surrounding two black holes that are rotating around one another and where the black hole is influencing the motion of an object.

"Accretion disks are ubiquitous features in the universe and can be found around smaller stars or stellar remnants, in close binary stars, in the centers of spiral galaxies, in quasars, they form also in gamma-ray bursts."

An accretion disk can be thought of as a large moving belt of asteroids that revolves around a gravitational body that eventually hits it. Essentially, an accretion disk is a large dense chunk of material that revolves around a large gravitational force, and eventually it revolves into the force itself.

No, the terms "ergosphere" and "accretion disk" are not interchangeable. An accretion disk is a structure created when matter, usually gas and dust, is drawn towards a rotating black hole and gradually falls into it. An ergosphere is the area surrounding a black hole where spacetime is pulled along with the hole's rotation.