Orlop

King James Dictionary

Or'Lop, n.

In a ship of war, a platform of planks laid over the beams in the hold, on which the cables are usually coiled. It contains also sail-rooms, carpenters' cabins and other apartments.

Also, a tier of beams below the lower deck for a like purpose.

Webster's Dictionary

(n.) 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.