Provide with a piece from Carmen (3)
I believe the answer is:
arm
'provide' is the definition.
(arming is a kind of providing)
'piece from carmen' is the wordplay.
'piece from' says the answer is hidden in the clue.
'ARM' can be found hidden inside 'carmen'.
'with a' acts as a link.
(Other definitions for arm that I've seen before include "Part of chair" , "What soldiers do" , "Equip with weapon" , "ready for war" , "Body part" .)