Under-sea is a term used to describe the underwater environment or things that exist beneath the surface of the sea. Synonyms for under-sea include submerged, subaqueous, submersed, bottom-dwelling, and suboceanic. These words imply that something is located or occurring below the sea level, whether it is an object, plant or animal. Other related terms include marine, aquatic, oceanic, and deep-sea. These words help describe the fascinating and sometimes mysterious world that exists beneath the waves. Humans are continuously discovering new species and ecosystems hidden beneath the under-sea environment, making it an exciting and intriguing subject area for research and exploration.