Transom and Two-by-four

Transom noun - A horizontal crosspiece across a window or separating a door from a window over it.

Two-by-four and transom are semantically related. In some cases you can use "Two-by-four" instead a noun "Transom".

Two-by-four noun - A timber measuring (slightly under) 2 inches by 4 inches in cross section.

Transom and two-by-four are semantically related. Sometimes you can use "Transom" instead a noun phrase "Two-by-four".