abyssal zone
Oceanographic term for the deep-sea layer typically below 2000–4000 meters, characterized by high pressure, low temperature, and absence of light.
A unique ecosystem exists in the abyssal zone.
bathyal zone; midnight zone; bathypelagic zone
hadal zone; hadopelagic zone; trench zone
Compound of 深海 (deep sea) and 帯 (zone, belt). A straightforward modern scientific term.