Thalassophobia, as the name suggests, is a specific type of phobia — an extreme or irrational fear or aversion. The term stems from the Greek phobos, meaning “fear,” and thalassa, meaning “sea.” Generally, people who suffer from thalassophobia become incredibly anxious around deep bodies of water. They may even avoid them outright.

Thalassophobia is a specific phobia that involves a persistent, intense fear of deep bodies of water such as the ocean or a lake. It stems from the Greek word thalassa ("the sea") and phobos ("fear"). Although not recognized as a distinct disorder by the DSM-5, its symptoms meet the diagnostic criteria for specific phobias.