Definition of flashing in US English:



  • A strip of metal used to stop water from penetrating the junction of a roof with another surface.

    ‘flashings around chimneys’
    ‘the lead flashing on the roof’
    • ‘Also check eaves, verges and ridges, and make sure that mortar, pointing and lead flashings are all in place around a chimney.’
    • ‘Site-built or factory-supplied flashings are used to seal the roofing around the curb.’
    • ‘The coping, flashings and most of the rendering would need to be removed.’
    • ‘The trapped water may accumulate to levels higher than the roof flashings, resulting in water leaks.’
    • ‘It was also used for roof flashings and weights for scales.’


Late 18th century: from the earlier synonym flash (of unknown origin) + -ing.