What is Fahrenheit measured in?

Fahrenheit is an old temperature scale named after Daniel Gabriel Fahrenheit (1686-1736), the German physicist who proposed it in 1724. It is still used in the USA. In this scale, the freezing point of water is 32 degrees Fahrenheit (°F) and the boiling point 212 °F, placing the boiling and freezing points of water exactly 180 degrees apart. A degree on the Fahrenheit scale is 1/180th part of interval between the ice point and steam point or boiling point. On the Celsius scale, the freezing and boiling points of water are exactly 100 degrees apart, hence the unit of this scale. A temperature interval of one degree Fahrenheit is an interval of 5⁄9 of a degree Celsius. The Fahrenheit and Celsius scales coincide at −40 degrees; i.e. −40 °F and −40 °C describe the same temperature.