'Underneath' in the Bible

The Lord said unto my Lord, Sit thou on my right hand, Till I put thine enemies underneath thy feet?

Jesus answered and said unto him, Because I said unto thee, I saw thee underneath the fig tree, believest thou? thou shalt see greater things than these.

Then the disciple whom Jesus loved said to Peter, "It is the Lord!" So Simon Peter, when he heard that it was the Lord, tucked in his outer garment (for he had nothing on underneath it), and plunged into the sea.

And the four living creatures, each one of them having six wings, are full of eyes all over and within [underneath their wings]; and day and night they never stop saying,“Holy, holy, holy [is the] Lord God, the Almighty [the Omnipotent, the Ruler of all], who was and who is and who is to come [the unchanging, eternal God].”

And no one was able in the heaven, or upon the earth, or underneath the earth, to open the book, or to regard it.

And when it opened the fifth seal, I saw underneath the altar the souls of them that had been slain for the word of God, and for the testimony which they held;