There isn't a single, universally accepted word for a mix of saltwater and freshwater. However, depending on the context, you can use terms like:

General Terms:

* Brackish water: This is the most common and accurate term for water with a salinity level between that of freshwater and seawater.

* Saline water: This is a broader term for any water that contains dissolved salts, but it's less specific than "brackish."

* Estuarine water: This term refers to water found in estuaries, which are areas where freshwater rivers meet the ocean.

More Specific Terms:

* Mesohaline water: This term refers to brackish water with a salinity level of 5-18 parts per thousand.

* Polyhaline water: This term refers to brackish water with a salinity level of 18-30 parts per thousand.

The best term to use will depend on the specific situation and the level of detail you want to convey.