The Greek noun abyssos (ἄβυσσος) comes from a- (without) and byssos (bottom/depth) — literally "the bottomless". In classical Greek it described any unfathomably deep place. In the Septuagint (Greek Old Testament), it translates the Hebrew tehom (the primordial deep, Genesis 1:2). In the New Testament, it appears 9 times — most in Revelation — referring to the realm of imprisoned demonic spirits (Luke 8:31) and the domain from which the beast arises (Revelation 11:7; 17:8) and where Satan is bound (Revelation 20:1–3).
The abyssos is Scripture's most vivid image for the cosmic dimension of evil — a prison-realm for forces that stand against God. In Luke 8:31, the demons beg Jesus not to send them into the abyss — even demonic forces fear the divine quarantine. Romans 10:7 uses it as a synonym for the realm of the dead: "Who will descend into the deep to bring Christ up from the dead?" — a rhetorical contrast to the nearness of the word of faith. In Revelation, the abyss is explicitly under divine control: an angel with the key descends to lock Satan in (Revelation 20:1–3). The bottomless pit has a bottom after all — the sovereignty of God. No depth exists beyond Christ's reach.