Abyss

(n.) A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable, and, specifically, hell, or the bottomless pit.

Abyss - Other Definitions

(n.) A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable, and, specifically, hell, or the bottomless pit.
(n.) Infinite time; a vast intellectual or moral depth.
(n.) The center of an escutcheon.