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Phrase(s): flash on
[for a light] to turn on suddenly. • The light flashed on and woke us up. • When the light flashed on, I had just been getting to sleep., Phrase(s): flash on something
Sl. to remember something suddenly and vividly. • Then I flashed on a great idea. • I was trying to flash on her name, but I couldn’t bring it to mind., Phrase(s): flash on someone or something
[for a light] to shine on someone or something suddenly or in bursts. • The orange neon light flashed on John’s face, making him look quite strange. • The light flashed on the window shade, startling the occupants of the room.
McGrawhill's American Idioms And Phrasal Verbs