- abyss
- late 14c., earlier abime (c.1300), from L.L. abyssus "bottomless pit," from Gk. abyssos (limne) "bottomless (pool)," from a- "without" (see a- (2)) + byssos "bottom," possibly related to bathos "depth." Abyssal is first recorded 1690s, used especially of the zone of ocean water below 300 fathoms.