ἄβυσσος

Greek ἄβυσσος (ábyssos) means 'bottomless' — from a- (without) + byssós (bottom, depth). It first described the primordial deep waters in Greek cosmology, the unfathomable void beneath the earth.

The word gained its most powerful resonance through the Septuagint, the Greek translation of the Hebrew Bible, where it rendered the Hebrew tehom — the formless deep over which God's spirit hovered at creation. In Revelation, the Abyss became the prison of demons.

Latin borrowed it as abyssus, which traveled into Old French as abisme, then into English as both 'abyss' and 'abysm.' The scientific term 'abyssal zone' now names the ocean floor below 4,000 meters — a place as alien as outer space.

Nietzsche gave the word its most quoted modern use: 'If you gaze long into an abyss, the abyss also gazes into you.' The bottomless pit became a metaphor for the darkness within.