A power of attorney document.

(typography, uncountable) The distinction between majuscule (uppercase) and minuscule (lowercase) letters. / (countable) A case used for carrying written letters.

(calligraphy) A highly calligraphic Western European script style used from approximately 1150.

An explosive device sent through the post, triggered to explode when the letter or packet is opened. / (computing) A virus contained within an email or similar file.

A letter written about the author's love for the intended reader. / (figuratively) A work that shows great passion or enthusiasm for something.

(US) Alternative spelling of Greek-letter

(finance) A letter that is not legally binding but provides some form of assurance about the financial position of an entity.

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

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

An aerogram; a letter sent by airmail.