An orlop deck is the lowest, often partial, deck in a ship with four or more decks, situated below the lower gun deck and just above the hold, typically used for storing cables, sails, and provisions. Originating from Dutch (overloop) and Middle English, it was often used as a midshipmen's mess or a lower deck surgery during battles.

Location: Below the waterline, positioned directly above the ship's hold.
Purpose: Primarily used for storage (cables, sails, food/supplies), it also housed crew quarters and the surgeon's, carpenter's, and pursers' cabins on warships.

Conditions: Situated deep inside the hull, it often lacked natural light and air.

Alternative Uses: During combat, the orlop deck—often being the lowest and safest spot from fire—was frequently used as a cockpit for treating the wounded.

Origin: The term derives from the Dutch word overloop or Middle Low German overl?p, meaning "something that overleaps".