beam 
(bēm)
(bēm)n.
1. A squared-off log or a large, oblong piece of timber, metal, or stone used especially as a horizontal support in construction.
2. Nautical
a. A transverse structural member of a ship's frame, used to support a deck and to brace the sides against stress.
b. The breadth of a ship at the widest point.
c. The side of a ship: sighted land off the starboard beam.
3. Informal The widest part of a person's hips: broad in the beam.
4. A steel tube or wooden roller on which the warp is wound in a loom.
5. An oscillating lever connected to an engine piston rod and used to transmit power to the crankshaft.
6.
a. The bar of a balance from which weighing pans are suspended.
b. Sports A balance beam.
7. The main horizontal bar on a plow to which the share, coulter, and handles are attached.
8. One of the main stems of a deer's antlers.
9.
a. A ray or shaft of light.
b. A concentrated stream of particles or a similar propagation of waves: a beam of protons; a beam of light.
10. A radio beam.
v. beamed, beam·ing, beams
v.intr.
1. To radiate light; shine.
2. To smile expansively.
v.tr.
Idiom: 1. To emit or transmit: beam a message via satellite.
2. To express by means of a radiant smile: He beamed his approval of the new idea.
on the beam
1. Following a radio beam. Used of aircraft.
2. On the right track; operating correctly.
[Middle English bem, from Old English bēam; see bheuə- in the Appendix of Indo-European roots.]