English Reference
noun

flashing

n.
US /ˈfɫæʃɪŋ/ UK /flˈæʃɪŋ/ flash·ing UK spelling flashings

  1. 01 B1 Intermediate

    the act of a light turning on and off very quickly.

    the intermittent emission or reflection of light, often used as a signal or indicator.

    Simple

    The flashing of the emergency lights warned drivers to slow down.

    In context

    The rhythmic flashing of the lighthouse provided a reliable navigational anchor for the sailors navigating the treacherous coastline.

    blinkingglimmeringsparkling
  2. 02 C2 Proficiency Technical Technical

    pieces of metal or plastic used to stop water from getting into the joints of a roof.

    strips of impervious material, typically lead or aluminium, installed to prevent water penetration at roof joints and penetrations.

    Simple

    The builder had to replace the lead flashing around the chimney to stop the leak.

    In context

    Improperly installed copper flashing at the valley of the roof led to significant structural rot over the course of a single decade.

    Usage

    Usually uncountable when referring to the material generally, but countable when referring to specific sections.

    weatherproofingsealant
  3. 03 C1 Advanced Informal Law

    the act of showing your naked body to someone in public for a short time.

    the act of briefly exposing one's genitals or naked body in a public place.

    Simple

    The man was arrested for flashing in the park near the school.

    In context

    The local authorities increased patrols following several reports of flashing in the residential district during the late evening hours.

    exposureindecency

But it backtracked from that account after footage emerged showing the Red Crescent and civil defence teams driving slowly with their emergency vehicle lights flashing and logos visible.

The Guardian· 19 Aug 2026

As the UN Secretary General António Guterres has put it, "every key climate indicator is flashing red".

BBC News· 15 Apr 2026

From flash + -ing. * (weatherproofing): From original flashing material of copper or aluminum that reflects flashes of sunlight.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C2 · Proficiency
Frequency Frequent
Updated