beam
n. countablen. a line of light shining from something, like the sun or a flashlight. It can also be a long, strong piece of wood or metal used to support a building's roof.
n. a narrow ray or line of light, energy, or particles; also, a long, sturdy piece of timber or metal used as a structural support in buildings or ships.
A beam of light shines through the window.
The old barn was supported by heavy wooden beams across the ceiling.
A single beam of moonlight illuminated the dust motes dancing in the otherwise silent, cavernous hall.
From Middle English beem, from Old English bēam (“tree, cross, gallows, column, pillar, wood, beam, splint, post, stock, rafter, piece of wood”), from Proto-West Germanic baum, from Proto-Germanic baumaz (“tree, beam, balk”), from Proto-Indo-European *bʰew- (“to grow, swell”). Cognate with North Frisian Boom, buum (“tree”), Saterland Frisian Boom (“tree”), West Frisian beam (“tree”), Cimbrian pome, póom, puam (“tree”), Dutch boom (“tree”), German Low German Boom (“tree”), German Baum (“tree”), Luxembourgish Bam (“tree”), Mòcheno pa'm (“tree”), Vilamovian baojm (“tree”), Yiddish בוים (boym, “tree”), Danish, Norwegian Bokmål, Norwegian Nynorsk, Swedish bom (“beam”), Icelandic baðmur (“tree”), Gothic 𐌱𐌰𐌲𐌼𐍃 (bagms, “tree”), Albanian bimë (“a plant”). Doublet of boom. The original English meaning of beam ("tree") is preserved in some compound words such as quickbeam. The verb is from Middle English bemen, from Old English bēamian (“to shine, to cast forth rays or beams of light”), from the noun.