In naval terminology, what does 'upstairs' refer to?

In naval terminology, the term "upstairs" refers to areas that are located topside, which means above the main deck of the ship. This can include the weather decks, flying bridges, or any upper-level structures that are above the operational areas of the ship. When crew members refer to moving "upstairs," they are indicating a movement towards these higher areas of the ship.

The other terms presented refer to different parts of the ship. For example, "below deck" points to areas under the main working and living quarters, "bottom level" suggests the lowest part of the ship, often associated with the bilge or hold, and "rear of the ship" identifies a specific geographical location on the ship rather than an elevation. Understanding these distinctions is vital for naval communication and operations.