Definition of main beam in English:

main beam

noun

  • 1A principal beam which transmits a load directly to a column.

    • ‘The piece cut off the frame is used for the main beam of the arch.’
    • ‘There are also unsafe parts of the building as the stairs have dry rot and the main beam is rusting badly.’
    • ‘All columns and main beams are 200 mm square laminated pine members, while secondary roof elements, roof linings and most other woodwork are made of untreated pine, the aroma of which permeates the whole complex.’
    • ‘The primary structure was a box beam, comprising two main beams.’
    • ‘The curving involved one main beam and railing.’
  • 2British The full (rather than dipped) beam of the headlights of a motor vehicle.

    ‘headlights were good, particularly on main beam’
    • ‘It is not lit all the way, but because of the traffic you can never be sure whether you should dip your lights or have them on main beam.’
    • ‘Mr Amor, of Great Cheverell, said: ‘I had my headlights on main beam when I saw something on the side of the road looking back at me.’’
    • ‘Designed primarily for off-road use, the lamps operate only when main beam is selected, a literally brilliant safety extra when driving on country roads at night.’
    • ‘The lights are good on dip and brilliant on main beam with good spread coverage.’
    • ‘The full light output is used for the main beam and a shutter blocks off part of the light when a dipped beam is required.’