a device that simultaneously discharges a flashbulb and operates a camera shutter.
Origin of flashgun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a type of electronic flash, attachable to or sometimes incorporated in a camera, that emits a very brief flash of light when the shutter is open
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