Beam

[1] A projection of light. A collimated, or approximately unidirectional, flow of electromagnetic radiation (radio, light, X-rays), or of particles (atoms, electrons, molecules). The angular beam width is defined by the half-intensity points.
See also asymmetrical beam, dipped beam, headlight beam setting, high beam, high beam indicator, low beam, main beam, main beam indicator, sealed beam
[2] A supporting bar. A bar or member which is loaded transversely, predominantly in bending
See also asymmetrical beam, cant beam, deck beam, door beam, hatch beam, I-beam, knee, beam, molded beam, pulling beam, side impact intrusion beam, transom beam
[3] The width of a ship. Also called breadth.
[4] A wooden or metal cylinder having large flanges at each end. Warp yarns are wound on the beam from cones or cheeses correctly arranged for inserting into the loom or warp-knitting machine. Beams are also used to furnish thread during lace making.