A debit note is a document issued by a buyer to a seller, indicating a return of goods received on credit or a request for a credit adjustment. It serves as a formal request for a reduction in the amount owed to the seller. 

A debit note typically includes details such as the date, invoice number, description of goods, reason for the debit note, and the amount to be adjusted. It is an important document for maintaining accurate financial records and ensuring transparency in transactions between buyers and sellers.