Older unit of absolute temperature. One degree (1°) rankine represents the same temperature difference as one degree on Fahrenheit scale, but the zero point of the scale is set at absolute zero. Thus, the rankine temperature is 459.67° plus the Fahrenheit temperature. One degree rankine is equal to five-ninth (0.55) of kelvin. Named after the Scottish engineer William Rankine (1820-70) who devised a cycle of operations in a heat engine (the Rankine Cycle).