ἄβυσσος

And the demons kept begging Jesus not to order them to go into the Abyss.

When the two witnesses have finished their testimony, the beast that comes up from the Abyss will wage war with them, and will overpower and kill them.

The beast that you saw—it was, and now is no more, but is about to come up out of the Abyss and go to its destruction. And those who dwell on the earth whose names were not written in the Book of Life from the foundation of the world will marvel when they see the beast that was, and is not, and yet will be.

Then I saw an angel coming down from heaven with the key to the Abyss, holding in his hand a great chain.

And he threw him into the Abyss, shut it, and sealed it over him, so that he could not deceive the nations until the thousand years were complete. After that, he must be released for a brief period of time.