|See also abyssal of, relating to, or constituting the zones of the oceans deeper than abyssal: below about 6000 metres (18 000 ft)|
|[C20: from French, from Hadés|
|hadal (hād'l) Pronunciation Key
Relating to the deepest regions of the ocean, below about 6,000 m (19,680 ft). The hadal zone mostly comprises trenches that can reach depths greater than 10,000 m (32,800 ft).