Attributive Designating a scale of absolute temperature (i.e. one with its zero identified with absolute zero) in which the degrees are equal in size to those on the Fahrenheit scale; especially in "Rankine scale".
The relationships between the Rankine scale and other scales are as follows (F = Fahrenheit, C = Celsius): °R = °F + 459.67 = (°C + 273.15) × 9/5.
As postpositive. Of a thermometric degree or specified number of degrees: measured on the Rankine scale.
Mid 19th century (in an earlier sense). From the name of William John Macquorn Rankine, Scottish physicist and engineer.