Fold part of zinc rim, perhaps (5)
I believe the answer is:
crimp
'fold' is the definition.
(I know that crimp is a more specific form of the action fold)
'part of zinc rim perhaps' is the wordplay.
'part of' says the answer is hidden in the clue.
'CRIMP' can be found hidden inside 'zinc rim perhaps'.
(Other definitions for crimp that I've seen before include "Fold or press into ridges" , "Press into small folds or ridges" , "wave" , "Curl hair tightly" , "Compress into small folds or ridges" .)