Kind, sort (4)
I believe the answer is:
type
This clue is a double definition.
'kind' is the first definition.
(I know that type is a type of kind)
'sort' is the second definition.
(type is a kind of sort)
(Other definitions for type that I've seen before include "Character" , "Stamp" , "Write letters" , "Sort, variety" , "get words on to paper?" .)