- a horizontal structural member, usually transverse, for supporting the decks and flats of a vessel.
- the extreme width of a vessel.
- the shank of an anchor.
- walking beam.
- (in a loom) a roller or cylinder on which the warp is wound before weaving.
- a similar cylinder on which cloth is wound as it is woven.
verb (used with object)
verb (used without object)
- not on the course indicated by a radio beam.
- Informal.wrong; incorrect: The pollsters were off the beam again for the last presidential election.
- on the course indicated by a radio beam, as an airplane.
- Nautical.at right angles to the keel.
- Informal.proceeding well; correct; exact: Their research is right on the beam and the results should be very valuable.
Origin of beam
Synonyms for beam
- not following a radio beam to maintain a course
- informalwrong, mistaken, or irrelevant
- following a radio beam to maintain a course
- nauticalopposite the beam of a vessel; abeam
- informalcorrect, relevant, or appropriate
Word Origin for beam
"emit rays of light," early 15c., from beam (n.) in the "ray of light" sense. Sense of "to smile radiantly" is from 1804; that of "to direct radio transmissions" is from 1927. Related: Beamed; beaming.
Old English beam originally "living tree," but by late 10c. also "rafter, post, ship's timber," from Proto-Germanic *baumaz (cf. Old Norse baðmr, Old Frisian bam "tree, gallows, beam," Middle Dutch boom, Old High German boum, German Baum "tree," Gothic bagms), perhaps from PIE verb root *bheue- "to grow" (see be). The shift from *-au- to -ea- is regular in Old English.
Meaning "ray of light" developed in Old English, probably because it was used by Bede to render Latin columna lucis, the Biblical "pillar of fire." Nautical sense of "one of the horizontal transverse timbers holding a ship together" is from early 13c., hence "greatest breadth of a ship," and slang broad in the beam "wide-hipped" (of persons). To be on the beam (1941) was originally an aviator's term for "to follow the course indicated by a radio beam."
off the beam
Off course, on the wrong track, as in He's way off the beam with that argument. This colloquial term and its antonym, on the beam, meaning “on the right track,” allude to directing aircraft by means of radio beams. [Colloquial; mid-1900s]
see broad in the beam; off the beam.