Réaumur scale, a temperature scale in which the boiling point of water is 80 degrees and its freezing point is 0 degrees.

(chiefly as postmodifier) Measured on the Réaumur scale.

A temperature scale on which 0 °C is 0 and 100 °C is 80. / (historical) A temperature scale on which water freezes at 0 and the alcohol mixture expands by 8% and boils at 80.