abyss

UK: /æˈbɪs/ US: /əˈbɪs/ ,(ə bis′)

WordReference Random House Learner's Dictionary of American English © 2025

a•byss /əˈbɪs/   n. [countable]

1. a deep space, hole, or cavity too vast to be measured.
2. the lowest or most hopeless depths;
   hell.

WordReference Random House Unabridged Dictionary of American English © 2025

a•byss  (ə bis′), n. 

1. a deep, immeasurable space, gulf, or cavity;
   vast chasm.
2. anything profound, unfathomable, or infinite:
   the abyss of time.
3. Mythology (in ancient cosmogony)
   • Philosophy the primal chaos before Creation.
   • Philosophy the infernal regions;
     hell.
   • a subterranean ocean.

• Greek ábyssos bottomless, equivalent. to a- a-⁶ + byssós bottom of the sea
• Late Latin abyssus
• earlier abisse, Middle English abissus 1350–1400

Abyss., 

1. Place Names Abyssinia.
2. Abyssinian.

Collins Concise English Dictionary © HarperCollins Publishers::

abyss / əˈbɪs/ noun

1. a very deep or unfathomable gorge or chasm
2. anything that appears to be endless or immeasurably deep, such as time, despair, or shame
3. hell or the infernal regions conceived of as a bottomless pit

Etymology: 16th Century: via Late Latin from Greek abussos bottomless (as in the phrase abussos limnē bottomless lake), from a-¹ + bussos depth