Meaning

noun a signal transmitted along a narrow path; guides airplane pilots in darkness or bad weather

noun long thick piece of wood or metal or concrete, etc., used in construction

noun a group of nearly parallel lines of electromagnetic radiation

originEtymology tree Proto-Germanic *bagmaz? Proto-West Germanic *baum Old English bēam Middle English beem English beam 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”).…

Etymology from Wiktionary, CC BY-SA 3.0