Law to revise when holding copyright (5)
I believe the answer is:
edict
'law' is the definition.
(I've seen this before)
'revise when holding copyright' is the wordplay.
'revise' becomes 'edit' (I've seen this in another clue).
'when holding' means one lot of letters goes inside another.
'copyright' becomes 'C' (as in the copyright symbol, a C in a circle).
'edit' placed around 'c' is 'EDICT'.
'to' is the link.
(Other definitions for edict that I've seen before include "Order issued by an authority" , "Legally binding proclamation" , "Decree, fiat" , "Decree, order" , "Pronouncement" .)