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.