Original: The symbol for degrees Rankine is Â R (or Â Ra if necessary to distinguish it from the RÃ mer and RÃ aumur scales). Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale.
Simplified: The Kelvin and Rankine temperature scales are defined so that absolute zero is 0 kelvins (K) or 0 degrees Rankine (Â R).