Which term refers to all floors that are below the main deck?

The term that refers to all floors that are below the main deck is "below deck." In naval terminology, this phrase is used to describe any space or area situated beneath the main deck of a ship. Understanding this concept is crucial for recognizing the layout and functionality of a vessel, as many systems, storage areas, and living quarters are located below the main deck.

"Overhead" typically refers to the ceilings of compartments that are found below the main deck, while "deck" actually denotes the various horizontal surfaces of the ship, including both the main and any upper decks. "Compartment" is a term that specifies individual enclosed spaces within the ship, typically used for specific functions or storage, but does not encompass all areas below the main deck.

Thus, "below deck" is the most accurate term to describe the entirety of those spaces underneath the main deck.