Definition of fluoride for English Language Learners. : a chemical that is sometimes added to drinking water and toothpaste to help keep teeth healthy.
Fairfax is an incorporated town in Marin County, California, United States. Fairfax is located 3.25 miles (5.2 km) west-northwest of San Rafael, at an elevation of 115 feet (35 m). The population is 7,441 at the 2010 census. Fairfax is the only town in America that holds a Green Party majority in the town council.
According to the U.S. Census Bureau, the county has a total area of 406 square miles (1,050 km2), of which 391 square miles (1,010 km2) is land and 15 square miles (39 km2) (3.8%) is water. Fairfax County is bounded on the north and southeast by the Potomac River.