Submersibles are vehicles that can navigate underwater, and there are several synonyms used to describe them. Some of the most commonly used synonyms include submarines, deep-sea vessels, underwater craft, and submersible vehicles. These words are often used to refer to machines or vehicles designed for underwater exploration or military purposes. Other synonyms for submersibles include bathyspheres, which are spherical vessels used to explore the ocean depths, and ROVs (remotely operated vehicles), which are controlled from the surface. Whichever synonym is used, submersibles represent an important technology for studying the oceans and exploring their depths.