abyssal plain

Noun

 * 1)  A large expanse of very flat and smooth ocean floor, usually found at depths of 4,600 to 5,500 meters (15,000 to 18,000 feet).

Translations

 * Catalan:
 * Finnish: syvänmeren tasanko
 * Hungarian: abisszikus síkság
 * Irish: má aibhéiseach
 * Portuguese: planície abissal