A letter from a wife or girlfriend to her husband or boyfriend, informing that the relationship is over. Usually precipitated by the writer's having met a third party.

(historical) The letter "A" in scarlet cloth required to be worn by those convicted of adultery in 17th-century Puritan New England.

A letter or written communication that serves to introduce an accompanying document; especially, a letter that introduces a résumé or curriculum vitae.

(US) A letter mailed at a post office and either kept for general delivery, or delivered to a post office box, at that same post office.

A letter that is written generically with blanks to be filled in with individual details, often sent in bulk, and frequently regarded as impersonal.

An employee of the post office who delivers mail (post) to, and collects it from, a residence or business, or from public mailboxes.

An aerogram; a letter sent by airmail.

A day marked in red on calendars; a church feast day. / (idiomatic) A particularly significant day; a day of personal or sectarian celebration.

A knifelike device with a blunt edge, used for slicing letters open.

(nautical, historical) An official commission from a government authorizing someone to seize the property or people of another nation; especially to attack merchant shipping of another nation.