One of the two subdivisions -- along with the Neritic -- of the Pelagic Zone out there in the big blue wet thing. The oceanic zone extends from the continental break (usually about 200 meters deep) and outward.

The oceanic zone is separated further into four environmental divisions:
Depth: down to about 200 meters
Most sunlight dissipates in this zone, but there is enough present for the process of photosynthesis. Areas with ample light for photosynthesis are part of the Photic zone. Areas without are part of the Aphotic zone (basically everything besides the Epipelagic).
Depth: from 200 to 900 meters
Often dubbed the 'twilight zone', very little natural light enters here -- definitely not enough for photosynthesis.
Depth: from 900 to 3000 meters
The only light present in this environment is that which is created by the bioluminescent organisms native to the region.
Depth: 3000 meters and below
Absolutely no light enters this area. Be afraid, be very afraid.