Dictionary.com
definitions

flash burn

noun
  1. a burn produced by brief exposure to intense, radiant heat, as from an explosion.

Origin of flash burn

First recorded in 1945–50
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for flash burn

flash burn

noun
  1. pathol a burn caused by momentary exposure to intense radiant heat
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012