1)
A licence presented by kings and queens allowing Pirates to legally and for a salary, plunder other countries navies and opposing pirates or privateers. Essentially its the document permitting and defining
one as a privateer.
or
2)
The debut album of the greatest Pirate band ever in the
history and future, Wheels of Poseidon.
Sir Francis Drake was given a Licence to Pillage by Queen Elizabeth I of
England allowing him to plunder the Spanish navy.
Little
Jimmy got a Licence to Pillage in his Christmas stocking one year and was really
happy because he really liked pirates.