flash up(redirected from flashing up)
1. To flash very brightly and suddenly. The lightning had only just flashed up when the crack of the thunder boomed nearby. The car's headlights flashed up, signaling me that a speed trap was nearby.
2. Of a computer notification or message, to appear on the screen very suddenly. By the time the warnings began flashing up on our screens, the reactor had already begun to melt down. A little message flashed up in the bottom corner of my browser telling me that I had won $1 million.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
flash something up (some place)
to shine a light upwards toward something. Flash your light up into the tree. She flashed up her light at the cat in the tree. Gloria flashed the light up.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.