n.1 a horizontal bar of wood or stone across a window or the top of a door (cf. MULLION).
2 each of several beams fixed across the stern-post of a ship.
3 a beam across a saw-pit to support a log.
4 a strengthening crossbar.
5 US transom window .
Phrases and idioms:
transom window
1. a window divided by a transom.
2 a window placed above the transom of a door or larger window; a fanlight.
Derivatives:
transomed adj.
Etymology: ME traversayn, transyn, -ing, f. OF traversin f. traverse TRAVERSE