1. To burst forth into or as if into flame.
2. To give off light or be lighted in sudden or intermittent bursts.
3. To appear or occur suddenly: The image flashed onto the screen.
4. To move or proceed rapidly: The cars flashed by.
5. To hang up a phone line momentarily, as when using call waiting.
6. Slang To think of or remember something suddenly: flashed on that time we got caught in the storm.
7. Slang To expose oneself in an indecent manner.

1. 1. To cause (light) to appear suddenly or in intermittent bursts.
   2. To cause to burst into flame.
   3. To reflect (light).
   4. To cause to reflect light from (a surface).
2. To make known or signal by flashing lights.
3. To communicate or display at great speed: flashed the news to the world capitals.
4. To exhibit briefly.
5. To hang up (a phone line) momentarily, as when using call waiting.
6. To display ostentatiously; flaunt.
7. To fill suddenly with water.
8. To cover with a thin protective layer.

1. A sudden, brief, intense display of light.
2. A sudden perception: a flash of insight.
3. A split second; an instant: I'll be on my way in a flash.
4. A brief news dispatch or transmission.
5. Slang Gaudy or ostentatious display: "The antique flash and trash of an older southern California have given way to a sleeker age of cultural hip" (Newsweek).
6. A flashlight.
7. 1. Instantaneous illumination for photography: photograph by flash.
   2. A device, such as a flashbulb, flashgun, or flash lamp, used to produce such illumination.
8. Slang The pleasurable sensation that accompanies the use of a drug; a rush.
9. Obsolete The language or cant of thieves, tramps, or underworld figures.

1. Happening suddenly or very quickly: flash freezing.
2. Slang Ostentatious; showy: a flash car.
3. Of or relating to figures of quarterly economic growth released by the government and subject to later revision.
4. Of or relating to photography using instantaneous illumination.
5. Of or relating to thieves, swindlers, and underworld figures.

Synonyms: These verbs mean to send forth light. Flash refers to a sudden and brilliant but short-lived outburst of light: A bolt of lightning flashed across the horizon.
Gleam implies transient or constant light that often appears against a dark background: "The light gleams an instant, then it's night once more" (Samuel Beckett).
Glance refers most often to light reflected obliquely: Moonlight glanced off the windows of the darkened building.
Glint applies to briefly gleaming or flashing light: Rays of sun glinted among the autumn leaves.
Sparkle suggests a rapid succession of little flashes of high brilliance (crystal glasses sparkling in the candlelight), and glitter, a similar succession of even greater intensity (jewels glittering in the display case). To glisten is to shine with a sparkling luster: The snow glistened in the dawn light.
Shimmer means to shine with a soft, tremulous light: "Everything about her shimmered and glimmered softly, as if her dress had been woven out of candle-beams" (Edith Wharton).
Glimmer refers to faint, fleeting light: "On the French coast, the light/Gleams, and is gone; the cliffs of England stand,/Glimmering and vast, out in the tranquil bay" (Matthew Arnold).
To twinkle is to shine with quick, intermittent flashes or gleams: "a few stars, twinkling faintly in the deep blue of the night sky" (Hugh Walpole).
Scintillate is applied to what flashes as if emitting sparks in a continuous stream: "ammonium chloride . . . depositing minute scintillating crystals on the windowpanes" (Primo Levi). See Also Synonyms at moment.