Transom (architecture)
TRANSVERSE HORIZONTAL STRUCTURAL BEAM, BAR OF CROSSPIECE; ALSO SHORT FOR TRANSOM WINDOW/ TRANSOM LIGHT
Transom window; Transom light; Transom Window; Ranma (architectural); Crosspiece; Transom (architectural)
In architecture, a transom is a transverse horizontal structural beam or bar, or a crosspiece separating a door from a window above it. This contrasts with a mullion, a vertical structural member.