'Abyss' in the Bible

The fifth angel sounded, and I saw a star from the sky which had fallen to the earth. The key to the pit of the abyss was given to him.

He opened the pit of the abyss, and smoke went up out of the pit, like the smoke from a burning furnace. The sun and the air were darkened because of the smoke from the pit.

They have over them as king the angel of the abyss. His name in Hebrew is "Abaddon," but in Greek, he has the name "Apollyon."

When they have finished their testimony, the beast that comes up out of the abyss will make war with them, and overcome them, and kill them.

The beast that you saw was, and is not; and is about to come up out of the abyss and to go into destruction. Those who dwell on the earth and whose names have not been written in the book of life from the foundation of the world will marvel when they see that the beast was, and is not, and shall be present.

I saw an angel coming down out of heaven, having the key of the abyss and a great chain in his hand.

and cast him into the abyss, and shut it, and sealed it over him, that he should deceive the nations no more, until the thousand years were finished. After this, he must be freed for a short time.