transom

A horizontal crosspiece over a door or between a door and a window above it.

A small hinged window above a door or another window.

A horizontal dividing bar of wood or stone in a window.

A lintel.

Any of several transverse beams affixed to the sternpost of a wooden ship and forming part of the stern.

The aftermost transverse structural member in a steel ship, including the floor, frame, and beam assembly at the sternpost.

The stern of a square-sterned boat when it is a structural member.

The horizontal beam on a cross or gallows.