Temperature unit (6)
'temperature unit' is the definition.
(degree is a kind of temperature unit)
This is the entire clue.
(Other definitions for degree that I've seen before include "Extent - academic achievement" , "Award conferred on a 1 across" , "Academic award - stage on a scale" , "Award conferred by a college or university" , "displayed by small elevated circle" .)
'temperature unit' is the definition.
(I know that kelvin is a type of temperature unit)
This is all the clue.
(Other definitions for kelvin that I've seen before include "Scale of absolute temperature named for him" , "Scientist" , "British physicist, who gave his name to a temperature scale" , "SI base unit of thermodynamic temperature" , "degree in cryogenics?" .)