The BIC (Bank Identifier Code) is an internationally valid bank code defined by the SWIFT (Society for Worldwide Interbank Financial Telecommunication).
Together with the IBAN, the BIC code is required to make international SEPA payments and Euro transfers.
The BIC has the function of identifying a payee in both national and international payment transactions.
Often the BIC code is also called SWIFT code, because it is assigned by SWIFT.
You can check which BIC code belongs to your IBAN online here.