jack - a flag
Jack Ketch – Jack Ketch was a famous executioner employed by Charles II in the 1600s. By extension, the term Jack Ketch became a general euphemism for the hangman or the gallows. Pirates did not want an appointment to visit Jack Ketch.
jack tar – common English term to refer to a sailor in the Royal Navy (sometimes shortened to just tar.)
Jacob’s ladder - a ladder made of a series of planks tied between two ropes.
jib – a triangular sail with the leading corner affixed in front of the foremast, typically to the bowsprit.
jolly boat - a small boat carried aboard a ship.
Jolly Roger – the name for any pirate flag, but commonly thought of as the classic one featuring a skull and crossbones. Various theories as to the origin of the name exist, including a corruption of the French “jolie rouge,” meaning “pretty red.”
jury mast – a temporary mast, used to replace one that has been damaged until full repairs can be made.
keel – A large beam along the underside of a ship’s hull from bow to stern.
keelhaul – To punish someone by dragging him under the keel of a ship. A rope was looped from one side of the ship, underneath the water, below the keel, and up the other side. An unfortunate sailor would be tied to the rope, thrown overboard on one side, and pulled to the other. Risks included having your skin ripped open by the rough bottom of the boat and/or drowning.
killick – a small anchor, traditionally made of stone. Also the name of a character in the marvelous Aubrey-Maturin series of books, by Patrick O’Brian.
knave – a dishonest person.
