the term apostolic see can refer to any see founded by one of the apostles but when used with the definite article it is used in the catholic church to refer specifically to the see of the bishop of rome whom that church sees as successor of saint peter the chief of the apostles.
while apostolic see can refer to any see founded by any of the apostles the term is in this case used to refer to the see of the bishop seen as successor of the chief of the apostles saint peter.