What do we call flat, level parts of the ocean floor?

The term "abyssal plains" refers to the vast, flat areas of the ocean floor that extend across the deep ocean basins. These plains are typically found at depths ranging from 3,000 to 6,000 meters below sea level and are characterized by their smooth and almost featureless landscape. Abyssal plains are formed by the accumulation of sediments over time, which can consist of tiny particles falling from the water column, as well as volcanic ash and other materials that settle on the ocean floor. This makes them one of the most prominent features of the ocean floor and an integral part of Earth's geological structure.

In contrast, seamounts are underwater mountains formed by volcanic activity, mid-ocean ridges are underwater mountain ranges formed by tectonic plate movements, and continental terraces refer to the submerged extensions of continental landmasses rather than flat oceanic features. Each of these alternatives represents different geological formations that do not match the description of flat, level parts of the ocean floor as accurately as abyssal plains do.