Definition of "letterbox" []

• See mailbox. (noun)
• A format for presenting movies on television that maintains the rectangular theater image on a television screen by reducing the overall image until the full width can be seen, resulting in blank space above and below the image. (noun)
• To produce or present (film) in a letterbox format. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Not like this man, when I'm drunk and they forgot to bring me the commercial mail, but when I'm tired and the mailman has indeed graced me with a load of advertisements while my letterbox is clearly marked with a large sticker that says:"
• "To within a few millimetres, human brains share a reading hotspot - what Stanislas Dehaene calls the "letterbox" - on the bottom of the left hemisphere."
• "His most recent leaflet through my letterbox was the most patronising I've ever received, incidentally."