The term 'ocean fill' can be defined as the process of filling an ocean with SEAWATER. SEAWATER is a type of saltwater that is found in oceans, seas, and other large bodies of water. It is composed of dissolved salts and other minerals, and its salinity levels vary depending on the location. SEAWATER is essential for the survival of marine life, and it also plays an important role in regulating the Earth's climate.