window

Concise Oxford English Dictionary © 2008 Oxford University Press:
window/ˈwɪndəʊ/

▶noun

• 1 an opening in a wall or roof, fitted with glass in a frame to admit light or air and allow people to see out.

  ■ an opening through which customers are served in a bank, ticket office, etc.

  ■ a space behind the window of a shop where goods are displayed.

  ■ (a window on/into/to) a means of observing and learning about.

• 2 a transparent panel in an envelope to show an address.

• 3 Computing a framed area on a display screen for viewing information.

• 4 an interval or opportunity for action.

• 5 Physics a range of electromagnetic wavelengths for which a medium (especially the atmosphere) is transparent.

• 6 strips of metal foil dispersed in the air to obstruct radar detection.

  ■ [military code word.]

– phrases
go out (of) the window informal (of a plan or behaviour) be abandoned or cease to exist.

windows of the soul the eyes.

– derivatives
windowed adjective,
windowless adjective.

– origin ME: from ON vindauga, from vindr ‘wind’ + auga ‘eye’.