Pick fruit with each tart oddly filling (8)
I believe the answer is:
plectrum
'pick' is the definition.
(a guitar pick)
'fruit with each tart oddly filling' is the wordplay.
'fruit with' becomes 'plum' (plum is a kind of fruit. I am not sure about the 'with' bit.**).
'oddly' indicates alternate letters.
'filling' indicates putting letters inside.
'each'+'tart'='eachtart'
The alternate letters of 'eachtart' are 'ectr'.
'plum' enclosing 'ectr' is 'PLECTRUM'.
Can you help me to learn more?
(Other definitions for plectrum that I've seen before include "Guitarist's implement" , "Object used to pluck stringed instrument" , "One for plucking guitar" , "Guitar plucker" , "Guitarist's aid" .)