Fahrenheit

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Of or relating to a temperature scale that registers the freezing point of water as 32° and the boiling point as 212° at one atmosphere of pressure. See Table at measurement.
2. Fahrenheit, Gabriel Daniel 1686-1736. German-born physicist who invented the mercury thermometer (1714) and devised the Fahrenheit temperature scale.

Century Dictionary and Cyclopedia

1. The name distinguishing the kind of thermometer-scale in most common use in Great Britain and the United States, in which the space between the freezing- and the boiling-point of water, under the standard pressure of the atmosphere, is divided into 180°, the freezing-point being marked 32°, and the boiling-point 212°: as, a temperature of 60° Fahrenheit (that is, according to the Fahrenheit scale). Each degree of the centigrade scale equals 1.8 degrees Fahrenheit, the centigrade zero being at the freezing-point, or 32° Fahrenheit. Abbreviated F. and Fahr. See thermometer and centigrade.

Wiktionary

1. adj. Describing a temperature scale originally defined as having 0 °F as the lowest temperature obtainable with a mixture of ice and salt, and 96 °F as the temperature of the human body, and now defined with 32 °F equal to 0 °C, and each degree Fahrenheit equal to 5/9 of a degree Celsius or 5/9 kelvin.

GNU Webster's 1913

1. adj. Conforming to the scale used by Gabriel Daniel Fahrenheit in the graduation of his thermometer; of or relating to Fahrenheit's thermometric scale. Used as an alternative to celsius.

WordNet 3.0

1. adj. of or relating to a temperature scale proposed by the inventor of the mercury thermometer
2. n. German physicist who invented the mercury thermometer and developed the scale of temperature that bears his name (1686-1736)