flash

Concise Oxford English Dictionary © 2008 Oxford University Press:
flash1

▶verb

• 1 shine in a bright but brief, sudden, or intermittent way.

• 2 move, pass, or send very quickly: a look of terror flashed across his face.

• 3 display or be displayed briefly or repeatedly.

  ■ informal display conspicuously so as to impress: they flash their money about.

  ■ informal (of a man) show one's genitals in public.

• 4 (flash over) make an electric circuit by sparking across a gap.

▶noun

• 1 a sudden brief burst of bright light.

• 2 a camera attachment that produces a flash of light, for taking photographs in poor light.

• 3 a sudden or brief manifestation or occurrence.

• 4 a bright patch of colour.

  ■ Brit. a coloured patch of cloth worn on a uniform as a distinguishing emblem.

• 5 (Flash) Computing (trademark in the US) an application used to produce animation sequences that can be viewed by a browser.

• 6 excess plastic or metal forced between facing surfaces as two halves of a mould close up.

• 7 a rush of water, especially down a weir to take a boat over shallows.

▶adjective

• 1 informal, chiefly Brit. ostentatiously stylish or expensive.

• 2 archaic relating to the language of criminals or prostitutes.

– phrases
flash in the pan a sudden but brief success that is unlikely to be repeated. [with allusion to the priming of a firearm, the flash arising from an explosion of gunpowder within the lock.]

– derivatives
flasher noun.

– origin ME (in the sense ‘splash water about’): prob. imitative; cf. flush1 and splash.

Concise Oxford English Dictionary © 2008 Oxford University Press:
flash2

▶noun Brit. a water-filled hollow formed by subsidence.

– origin ME (in the sense ‘a marshy place’): from OFr. flache, var. of Norman dial. flaque, from MDu. vlacke.