Copy page in souvenir article (7)
I believe the answer is:
replica
'copy' is the definition.
(replica is a kind of copy)
'page in souvenir article' is the wordplay.
'page' becomes 'p'.
'in' is an insertion indicator.
'souvenir' becomes 'relic' ('relic' can be a synonym of 'souvenir').
'article' becomes 'a' (indefinite article).
'p' put into 'relic' is 'replic'.
'replic'+'a'='REPLICA'
(Other definitions for replica that I've seen before include "Facsimile" , "Duplicate" , "Caliper (anag)" , "Reproduction, exact copy" , "Exact copy or model" .)