R'eaumur \R['e]`au`mur"\, a. Of or pertaining to Ren['e] Antoine Ferchault de R['e]aumur; conformed to the scale adopted by R['e]aumur in graduating the thermometer he invented. -- n. A R['e]aumur thermometer or scale.

Note: The R['e]aumur thermometer is so graduated that 0[deg] marks the freezing point and 80[deg] the boiling point of water. Frequently indicated by R. Cf. Centigrade, and Fahrenheit. See Illust. of Thermometer.

Source: Webster's Revised Unabridged Dictionary (1913)