Salt water, also known as saline water, is a mixture of salt and water. There are many synonyms for this common term, including brine, seawater, ocean water, and saline solution. Brine refers to water that has been saturated with salt, while seawater and ocean water specifically refer to water from the sea. Saline solution generally refers to a medical solution made up of salt and water. Other related terms include salted water, which usually means water that has been salted for cooking or preserving purposes, and saltwater aquariums, which are fish tanks filled with saltwater to create a natural habitat for marine life.