/flash"euhr/ , n.
1. a person or thing that flashes.
2. a flashing light operated by a switching device that automatically turns it on and off alternately.
3. a signal light on an automotive vehicle that can be made to flash, as to indicate the intention of making a turn or to call attention to a vehicle that has slowed or stopped in a hazardous place. Cf. turn signal .
4. the switching device that operates such a light.
5. Slang. a person, esp. a man, who exposes the genitals suddenly, and usually briefly, in public.
[ 1605-15; FLASH + -ER 1 ]