orlop

The lowest deck of a ship, especially a warship, having at least four decks.

Nautical, the deck below the berth-deck in a ship, where the cables were formerly coiled.

The lowest deck of a vessel, esp. of a ship of war, consisting of a platform laid over the beams in the hold, on which the cables are coiled.

The platform over the hold of a ship that makes up the fourth or lowest deck, hence in full called orlop deck, especially of a warship.

the fourth or lowest deck