transom

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A horizontal crosspiece over a door or between a door and a window above it.
2. n. A small hinged window above a door or another window.
3. n. A horizontal dividing bar of wood or stone in a window.
4. n. A lintel.
5. n. Nautical Any of several transverse beams affixed to the sternpost of a wooden ship and forming part of the stern.
6. n. Nautical The aftermost transverse structural member in a steel ship, including the floor, frame, and beam assembly at the sternpost.
7. n. Nautical The stern of a square-sterned boat when it is a structural member.
8. n. The horizontal beam on a cross or gallows.

Century Dictionary and Cyclopedia

1. n. One of the cross-ties or sleepers laid under the longitudinal sills of a permanent way for a street railway, or for any railway laid on this system, as in a mine.
2. n. In architecture, a horizontal bar of timber or stone across a window; also, the cross-bar separating a door from the fanlight above it. See mullion.
3. n. Same as transom-window, 2.
4. n. A slat of a bedstead.
5. n. Nautical, one of several beams or timbers fixed across the stern-post of a ship to strengthen the after part and give it the figure most suitable to the service for which the vessel is intended. See also cut under counter.
6. n. In a saw-pit, a joist resting transversely upon the strakes.
7. n. One of two beams of wood or metal secured horizontally to the side frames of a railway car-truck. They are placed one on each side of the swing-bolster.
8. n. In gunnery, a piece of wood or iron joining the cheeks of gun-carriages, whence the terms transom-plates, transom-bolts, etc.
9. n. In surveying, a piece of wood made to slide upon a cross-staff; the vane of a cross-staff.

Wiktionary

1. n. A crosspiece over a door; a lintel.
2. n. A horizontal dividing bar in a window.
3. n. nautical Any of several transverse structural members in a ship, especially at the stern; a thwart.
4. n. nautical The flat or nearly flat stern of a boat or ship.
5. n. The horizontal beam on a cross or gallows.
6. n. figuratively Items that have arrived over the transom.

GNU Webster's 1913

1. n. (Arch.) 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.
2. n. (Naut.) One of the principal transverse timbers of the stern, bolted to the sternpost and giving shape to the stern structure; -- called also transsummer.
3. n. (Gun.) The piece of wood or iron connecting the cheeks of some gun carriages.
4. n. (Surg.) The vane of a cross-staff.
5. n. (Railroad) One of the crossbeams connecting the side frames of a truck with each other.

WordNet 3.0

1. n. a window above a door that is usually hinged to a horizontal crosspiece over the door
2. n. a horizontal crosspiece across a window or separating a door from a window over it