Bible Dictionary
ABYSS
The abyss means a very deep or bottomless place. In the New Testament it is associated with the abode or confinement of demons and is distinguished from the final lake of fire.
Biblical Usage
In the New Testament the abyss is associated with the demons’ place of confinement and with the bottomless pit of Revelation. It is not the final lake of fire and brimstone, into which the Devil is ultimately cast.