'Opening' in the Bible

Then Nebuchadnezzar approached the opening of the blazing fire furnace. He shouted out, "Shadrach, Meshach, and Abednego, servants of the Most High God, come out and come here!" So Shadrach, Meshach, and Abednego came out of the fire.

A stone was brought and placed over the opening to the pit, and the king affixed a seal to it with his personal signet ring and with the signet rings of his officials so that no one would interfere with Daniel's situation.