A letter box is a receptacle for receiving mail.
Letterbox may also refer to:
Distribution of advertising mail by letter box drop Letterboxing (filming), the practice of transferring film shot in a widescreen aspect ratio to standard-width, resulting in a letterbox Letterboxing (hobby), outdoor orienteering game Letter Box (game show), a 1962 Australian game show "Letterbox", a song by They Might Be Giants from their 1990 album Flood Letterbox, a 2017 album by Marie Miller Device fingerprint § Offering a simplified fingerprint, also known as letterboxing, a method which mitigates Internet tracking by screen size
See also Letterboxd, a social networking site for films Party Time (TV series), an Australian game show