part of the open sea or ocean compormising the water coloumn ,other than that near the coast or the sea floor?

Question

what the name of this zone

Answer 1

There is one way of namin the three zones of the oceans from top to bottom
Epipelagic Shallow
Mesopelagic Middle
Bathypalagi Deepest

This does not quite fit the definition of your question though as you said near the coast, and sea floor. So I am not sure if this is what you are looking for as the upper area is still called Epipelagic even out in the middle of the ocean