Letterbox

n. video playback format in which the picture is displayed in the central portion of the screen with black bands at the top and bottom (so the wider film format will fit the dimensions of a TV screen)

v. (Video) display in letterbox format, display only across the center of a screen with black bands at the top and bottom (so the wider film format will fit the different dimensions of a TV screen);(British) mailbox, mail slot

Letterboxing is the practice of transferring widescreen films to video formats while preserving the original aspect ratio. Since the video display is most often a more square aspect ratio than the original film, the resulting video must include masked-off areas above and below the picture area (often referred to as "black bars," or, more accurately, as mattes). Letterboxing takes its name from the similarity of the resulting image to a horizontal opening in a postal letter box. LTBX is an acronym used for programming using this format.
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