Meaning ofletterboxedin English

Verb

1. transferred a movie to video with black bars; preserving aspect ratio
   The film was letterboxed to fit the widescreen format.
2. hunted for hidden containers with clues
   They went letterboxing in the woods, searching for hidden treasures.
3. delivered mail to a mailbox or slot
   The mailman letterboxed the package in the customer's mailbox.