Residence of Catholic dignitary in charge of French island (8)
I believe the answer is:
domicile
'residence' is the definition.
(I know that domicile is a type of residence)
'catholic dignitary in charge of french island' is the wordplay.
'catholic dignitary' becomes 'dom' (title for some Catholic monks, from Latin dominus).
'in charge of' becomes 'ic'.
'french island' becomes 'ile' ('island' in French).
'dom'+'ic'+'ile'='DOMICILE'
'of' is the link.
(Other definitions for domicile that I've seen before include "house" , "A person's principal home" , "Habitation" , "A person's place of residence" , "Place of residence, abode" .)