transom
Pronunciation: /ˈtrans(ə)m/
noun
- the flat surface forming the stern of a boat.
- a horizontal beam reinforcing the stern of a boat.
- a strengthening crossbar, in particular one set above a window or door. Compare with mullion.
- US term for transom window.


Origin:
late Middle English (earlier as traversayn): from Old French traversin, from the verb traverser 'to cross' (see traverse)