Real Dictionary

flash
Flash is the use of special bulbs to give more light when taking a photograph.
adjective: If you describe something as flash, you mean that it looks expensive, fashionable, and new.
countable noun: A flash is a sudden burst of light or of something shiny or bright.
countable noun: A flash is the same as a flashlight.
countable noun: You talk about a flash of something when you are saying that it happens very suddenly and unexpectedly.
verb: If a light flashes or if you flash a light, it shines with a sudden bright light, especially as quick, regular flashes of light.
verb: If a picture or message flashes up on a screen, or if you flash it onto a screen, it is displayed there briefly or suddenly, and often repeatedly.
verb: If someone's eyes flash, they suddenly show a strong emotion, especially anger.
verb: If something flashes past or by, it moves past you so fast that you cannot see it properly.
verb: If something flashes through or into your mind, you suddenly think about it.
verb: If you flash a look or a smile at someone, you suddenly look at them or smile at them.
verb: If you flash news or information to a place, you send it there quickly by computer, satellite, or other system.
verb: If you flash something such as an identity card, you show it to people quickly and then put it away again.

flash in American English
to send out or reflect a sudden, brief blaze or light, esp. at intervals
noun: a brief, sudden burst of bright light
noun: a precedence code for handling messages about initial enemy contact or operational combat messages of extreme urgency within the U.S. military

flash in British English
noun: a sudden short blaze of intense light or flame

flash in Chemical Engineering
noun: A flash is a process in which a liquid is vaporized in one stage.

flash in Mechanical Engineering
noun: Flash consists of unwanted material pushed out from the edges of a die during forming.