Transom

1. n. One of the crossbeams connecting the side frames of a truck with each other.
2. n. A horizontal crossbar in a window, over a door, or between a door and a window above it. Transom is the horizontal, as mullion is the vertical, bar across an opening. See Illust. of Mullion.
3. n. One of the principal transverse timbers of the stern, bolted to the sternpost and giving shape to the stern structure; — called also transsummer.
4. n. The piece of wood or iron connecting the cheeks of some gun carriages.
5. n. The vane of a cross-staff.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.