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Palisade: Wooden wall constructed around the edge of an enclosure. After the Conquest most of these wooden walls were replaced with stone.
Parapet: Low wall placed to protect any spot where there is a sudden drop, e.g. top of a wall.
Pipe Rolls: These were the oldest and longest series of public records providing information about the medieval finances of the king such as the cost of castle building and revenue from feudal fees. They were introduced by Henry I in 1130 and continued up until 1832.
Piscina: basin for washing the Communion or Mass vessels. Provided with a drain, and generally set in or against the wall to the South of an altar.
Portcullis: Iron gate constructed to rise and fall in vertical grooves; used in gateways of castles to prevent access by the enemy.