abyssal zone
Oceanography
noun
The deep part of the ocean, now typically from a depth of 3000 metres (1.9 miles) down to 6000 metres (3.7 miles), though the numerical limits, especially the upper one, vary.
- The term originally referred to a depth of 100 fathoms (approx. 183 metres) down to the lowest depth at which life is possible..
Origin
Mid 19th century.