Beam n.
 1. Any large piece of timber or iron long in proportion to its thickness, and prepared for use.
 2. One of the principal horizontal timbers of a building or ship.
    The beams of a vessel are strong pieces of timber stretching across from side to side to support the decks.   --Totten.
 3. The width of a vessel; as, one vessel is said to have more beam than another.
 4. The bar of a balance, from the ends of which the scales are suspended.
    The doubtful beam long nods from side to side.   --Pope.
 5. The principal stem or horn of a stag or other deer, which bears the antlers, or branches.
 6. The pole of a carriage. [Poetic]
 7. A cylinder of wood, making part of a loom, on which weavers wind the warp before weaving; also, the cylinder on which the cloth is rolled, as it is woven; one being called the fore beam, the other the back beam.
 8. The straight part or shank of an anchor.
 9. The main part of a plow, to which the handles and colter are secured, and to the end of which are attached the oxen or horses that draw it.
 10. Steam Engine A heavy iron lever having an oscillating motion on a central axis, one end of which is connected with the piston rod from which it receives motion, and the other with the crank of the wheel shaft; -- called also working beam or walking beam.
 11. A ray or collection of parallel rays emitted from the sun or other luminous body; as, a beam of light, or of heat.
    How far that little candle throws his beams!   --Shak.
 12. (Fig.): A ray; a gleam; as, a beam of comfort.
    Mercy with her genial beam.   --Keble.
 13. One of the long feathers in the wing of a hawk; -- called also beam feather.
 Abaft the beam Naut., in an arc of the horizon between a line that crosses the ship at right angles, or in the direction of her beams, and that point of the compass toward which her stern is directed.
 Beam center Mach., the fulcrum or pin on which the working beam of an engine vibrates.
 Beam compass, an instrument consisting of a rod or beam, having sliding sockets that carry steel or pencil points; -- used for drawing or describing large circles.
 Beam engine, a steam engine having a working beam to transmit power, in distinction from one which has its piston rod attached directly to the crank of the wheel shaft.
 Before the beam Naut., in an arc of the horizon included between a line that crosses the ship at right angles and that point of the compass toward which the ship steers.
 On the beam, in a line with the beams, or at right angles with the keel.
 On the weather beam, on the side of a ship which faces the wind.
 To be on her beam ends, to incline, as a vessel, so much on one side that her beams approach a vertical position.