letterbox

noun

1. (Commonwealth, Ireland, UK)A box into which mail is put.
2. (Commonwealth, Ireland, UK)A box into which mail is put.

   “A wad of junk mail was pushed through the letterbox in the front door and dropped onto the mat.”

3. A hidden container that holds a logbook and rubber stamp, found by following clues as a form of recreation.
4. A rectangular hole or slot.

   “His strength was running out fast: one more good letterbox was all that he could conceive himself able to make. He made it, hacking away with slow, painful strokes, his axe-handle slippery with his sweat.”

adj

1. (not-comparable)Transferred to home video formats while preserving the original aspect ratio, having black bars above and below the picture area.

verb

1. (transitive)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.
2. (intransitive, transitive)To hunt for letterboxes (containers with logbook and rubber stamp) by following clues.