There is a round opening in the wall thru which we see the blue sky of Africa.

The front door of the room had a round opening in the center.

There was a round opening in the top of that metal dome.

Central hall is surrounded by the main exhibition area, both are connected through a round opening between.

Richard saw the body at the same time as they approached the round opening into the vaults.

Just above the equatorial rim, small, round openings suddenly appeared.

They made a little round window, and left a round opening for an entrance.

To allow the head to pass through, there is a round opening in the middle with a vertical slit running down farther.

I find a round opening in the bottom of the reef.

In layman's terms, it is the round opening whose edges are the lowest ribs.