lazaretto
A between decks is the space between any two decks of a ship.
decks
space
The tween deck is any space between two continuous decks in the hull of a vessel, as between a shelter deck and a freeboard deck.
Rooms on a ship are called cabins and suites; floors are called decks.
They can be used on fairly long span bridges compared to suspension bridges by using pylons in between. They have better stability against wind loads. They can be constructed in steps working on their own decks.
It's called a shoe.
There is a great website called Aeclectic Tarot which has many tarot decks and reviews from customers for multiple decks.
It varies between the different classes: Constitution, Refit Constitution, Excelsior, Ambassador, Galaxy, and Sovereign Class ships each have different numbers of decks.
Titanic had eleven decks, eight of them were passenger decks.
The box is called a shoe.