We don't have synonyms for letterbox yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are letter box, litterbox and letterbomb.
°To transfer a widescreen motion picture to home video formats while preserving the original aspect ratio, with the placing of black bars above and below the picture area.
°To transfer a widescreen motion picture to home video formats while preserving the original aspect ratio, with the placing of black bars above and below the picture area.