abyssal

American  

[uh-bis-uhl] / əˈbɪs əl /

adjective

1. of or like an abyss; immeasurable; unfathomable.

2. Oceanography. of or relating to the biogeographic zone of the ocean bottom between the bathyal and hadal zones: from depths of approximately 13,000 to 21,000 feet (4,000 to 6,500 meters).

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abyssal British  

/ əˈbɪsəl /

adjective

1. of or belonging to the ocean depths, esp below 2000 metres (6500 feet)

   abyssal zone

2. geology another word for plutonic

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abyssal Scientific  

/ ə-bĭs′əl /

1. Relating to the greatest depths of the oceans and to the organisms that live there. The abyssal zone encompasses all depths below 4,000 m (13,120 ft).

2. Relating to the region of the ocean bottom between the bathyal and hadal zones, from depths of approximately 2,000 to 6,000 m (6,560 to 19,680 ft). The abyssal zone includes nearly two-thirds of the Earth's surface.

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Etymology

Origin of abyssal

First recorded in 1600–10; from Medieval Latin abyssālis, abyss, -al ¹

Example Sentences

On the seafloor, you can find canyons, volcanoes and vast abyssal planes.

From Salon • May 21, 2025

An underwater earthquake or a landslide can snap the cable deep in the abyssal zone.

From Los Angeles Times • Mar. 28, 2025

A group of British scientists is currently surveying species on the abyssal plain in the eastern Pacific.

From BBC • Mar. 17, 2024

These eddies are like giant whirlpools and often reach the abyssal seafloor, resulting in seafloor erosion and large sediment accumulations called contourites, akin to snowdrifts.

From Science Daily • Mar. 12, 2024

The hurried search of the decks, her frustration ceding to worry and abyssal panic when she realized the Assassin was no longer on board.

From "The Reader" by Traci Chee