What is the X in X-mas?
1753, named for Gabriel Daniel Fahrenheit (1686-1736), Prussian physicist who proposed the scale in 1714. An abstract surname meaning literally "experience."
Fahrenheit Fahr·en·heit (fār'ən-hīt')
Of or relating to a temperature scale that registers the freezing point of water as 32°F and the boiling point as 212°F at one atmosphere of pressure.
A temperature scale according to which water freezes at 32 degrees and boils at 212 degrees. The scale was devised by Gabriel Daniel Fahrenheit, an instrument maker of the eighteenth century, born in Germany.
A temperature scale, used primarily in the United States, in which the freezing point of water is 32 degrees and the boiling point 212 degrees. Temperatures in this scale are denoted by °F or, in scientific usage, F alone. (Compare Celsius.)