n. & v.
1. a long sturdy piece of squared timber or metal spanning an opening or room, usu. to support the structure above.
2 a a ray or shaft of light. b a directional flow of particles or radiation.
3 a bright look or smile.
4 a a series of radio or radar signals as a guide to a ship or aircraft. b the course indicated by this (off beam).
5 the crossbar of a balance.
6 a a ship's breadth at its widest point. b the width of a person's hips (esp. broad in the beam).
7 (in pl.) the horizontal cross-timbers of a ship supporting the deck and joining the sides.
8 the side of a ship (land on the port beam).
9 the chief timber of a plough.
10 the cylinder in a loom on which the warp or cloth is wound.
11 the main stem of a stag's antlers.
12 the lever in an engine connecting the piston-rod and crank.
13 the shank of an anchor.
1. tr. emit or direct (light, radio waves, etc.).
2 intr. a shine. b look or smile radiantly.
Phrases and idioms:
beam-compass (or -compasses) compasses with a beam connecting sliding sockets, used for large circles. a beam in one's eye a fault that is greater in oneself than in the person one is finding fault with (see Matt. 7:3). off beam colloq. mistaken. on the beam colloq. on the right track. on the beam-ends (of a ship) on its side; almost capsizing. on one's beam-ends near the end of one's resources.
Etymology: OE beam tree f. WG