• Letter (alphabet), a written element of an alphabet that represents a single phoneme
  • Letterform, typographic term for alphabetical letter shapes
• Letter (message), a form of written communication; see also mail
• Letters, the collected correspondence of a writer or historically significant person
  • Maktubat (disambiguation), the Arabic word for collected letters
  • Pauline epistles, addressed by St. Paul to various communities or congregations, such as "Letters to the Galatians" or "Letters to the Corinthians", and part of the canonical books of the Bible
• The letter as a form of second-person literature; see Epistle
  • Epistolary novel, a long-form fiction composed of letters (epistles)
• Letters, another word for literature, as in "arts and letters"
• LETTERS (novel), by John Barth
• Open letter, a public letter as distinguished from private correspondence
• Letter to the editor, a letter sent to a newspaper, magazine, or online publication by one of its readers and meant to be published
• Encyclical letter in the Catholic Church
• Letter (paper size), paper conventionally sized for letter-writing
• Varsity letter, an award given in the U.S. for interscholastic or intercollegiate merit in a sport or other activity such as band or choir.
• Rehearsal letter in an orchestral score
• Letters (Matt Cardle album)
• Letters (Aftershock album)
• Letters (Butch Walker album)
• Letters (Jimmy Webb album)
• Letters, a 2002 single by Hikaru Utada

• En typographie, une lettre est l'un des signes graphiques formant un alphabet et servant à transcrire une langue.
• Les lettres sont les disciplines académiques d'étude de la condition humaine par des méthodes analytiques, critiques ou spéculatives, les distinguant des approches empiriques des sciences naturelles et sociales, en combinant le français et la philosophie.
• Une lettre peut aussi désigner un courrier.

För Lettlands befolkning se Lettlands demografi. Se också letter (pappersformat).

Sztuką pisania listów, jako zjawiskiem kulturowym, zajmuje się epistolografia.