abyssal
/əˈbɪs(ə)l
/adjective chiefly technical
1Relating to or denoting the depths or bed of the ocean, especially between about 3000 and 6000 metres down: the abyssal depths of the Atlantic the genera found in the abyssal North Atlantic...
- They are found in every aquatic habitat from the abyssal depths of the ocean to freshwater streams and ponds; a few can even crawl on land for short periods of time.
- Bathyal is defined as pertaining to the ocean bottom between the sublittoral and abyssal zones - from depths of approximately 200 to 400 m.
- Technically, continental shelves are defined as the region of ocean floor between the coast and the shelf-break, where the seafloor steepens into the continental slope and plunges toward the abyssal depths.
1.1 Geology another term for plutonic (sense 1).The fluids that emerge may come in bursts when earthquakes occur; fluid flow may therefore repeat episodically over hundreds of thousands of years as abyssal hills are uplifted and spread away from the mid-ocean ridge crest....
- The width of the mountain is 4-6 times greater than that of most abyssal hills.
- The incoming sediments beneath the 3 km deep Oman abyssal plain consist of 3 km of Makran sands that are derived from the north.
Origin
Mid 17th century: from late Latin abyssalis 'belonging to an abyss' (see abyss).