Meaning of “flash” - Learner’s Dictionary

flash

noun uk us /flæʃ/
BRIGHT LIGHT [ C ]

B2 a sudden bright light:

The bomb exploded in a flash of yellow light.
CAMERA [ C, U ]

B2 a piece of camera equipment that produces a bright light when you take a photograph in a dark place

SUDDEN EXPERIENCE [ C ]

a sudden experience of something such as a feeling or idea:

a flash of anger
I had a flash of inspiration.
in a flash

immediately, or very quickly:

I'll be back in a flash.

(Definition of “flash noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)