society > travel > travel by water > vessel, ship, or boat > parts of vessels > part of vessel above water > [noun] > deck > upper deck (15)
a deck exposed to the weather; the uppermost unprotected deck other than the forecastle, bridge and poop.
in a ship, the second deck from above in all vessels of two or more decks; the only deck in a vessel of one deck.
elliptical for upper deck, storey, berth, etc.