What is the name of the upper complete deck on a ship?

The term "Main Deck" refers to the primary complete deck that runs the full length of a ship. It serves as the main operational area for activities and is typically the highest deck that is continuously above the waterline. The significance of the Main Deck lies in its multifunctional use, often housing various compartments, providing crew access to essential equipment and features, and serving as a primary area for deck operations.

Other decks mentioned, such as the Quarter Deck, Forecastle Deck, and Upper Deck, refer to specific structures or sections of the ship with distinct purposes. The Quarter Deck, for example, is a ceremonial area near the ship's entrance where formal duties may take place, while the Forecastle Deck is located at the front of the ship and usually has accommodations for the crew. The Upper Deck typically refers to any deck located above the Main Deck but does not necessarily denote the primary complete deck itself. Thus, "Main Deck" is the correct nomenclature for the upper complete deck on a ship.