The postal facility that deals with mail that cannot be delivered.

(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.

A reference to any of several of the strongest English swear words that are also four letters long, especially those composing the so-called seven dirty words.

(Scotland, law) A letter passing the signet, whereby a debtor is relieved from personal diligence, or whereby an outlaw is reponed against sentence of outlawry.

(obsolete) past participle of let

(obsolete, rare) Let; demised, leased.

A person who is professionally employed to add writing to something (as a sign, shop window, etc.)

Printed to a sufficient visual standard to be sent as a letter.

A portion of text at the top of a letter, identifying the sender and often giving their address etc., used for formal correspondence. / Paper marked with a letterhead.

Exactly correct, correct in every letter.