In a hospital, what does, "pool" mean.?!

In a hospital, what does, "pool" mean.?

is in their job listing. One job would say regular, the other one pool.

Thanks.

Somebody who works "pool" is sort of like a floater -- you're put on the unit where you're most needed.

A pool nurse may work in the ICU one night, the CCU the next . . . the ER or in Radiology -- you're sort of like the hospital b****. They shove you where they need you.