<p><strong>Noun</strong></p><ul><li>Chiefly British: a public or private mailbox.</li><li>Digital Technology, Television: a technique for displaying a wide-screen film or landscape video on a narrower screen by reducing its size but retaining the aspect ratio, with black bands filling the screen above and below the picture (often used attributively).<ul><li>Example: letterbox videos.</li></ul></li></ul><p><strong>Verb (used with object)</strong></p><ul><li>Digital Technology, Television: to display (a film or video) by using the letterbox technique.</li></ul>