👉 fathoms is a concept used in geography, specifically to denote the depth at which a sea level would be reached if it were to sink into the ocean. It was historically defined as 3 feet (0.9 meters) below sea level. However, this definition has been challenged by various scientific studies and interpretations of Earth's shape over time. Fathoms are also used in marine geology and can refer to a depth within a specific sedimentary layer or a specific location on the ocean