Writer ringing about a type of nut (5)
I believe the answer is:
pecan
'type of nut' is the definition.
(I know that pecan is a type of edible nut)
'writer ringing about a' is the wordplay.
'writer' becomes 'pen' (something which writes).
'ringing' indicates putting letters inside.
'about' becomes 'c' (abbreviation for circa).
'c'+'a'='ca'
'pen' enclosing 'ca' is 'PECAN'.
(Other definitions for pecan that I've seen before include "Something like a walnut" , "Walnut-like nut" , "nut-tree" , "Nut tree of the southern United States and Mexico" , "Species of hickory - edible nut" .)