The origins of these terms can be traced back to 1494 when the Italian Friar Luca-Pacioli first recorded the double-entry bookkeeping system. It was he that first described the use of the Latin terms ‘Credre’ and ‘Debere’ . In the 1500s, English translators used these Latin terms to create the terms ‘Debit and Credit’. The Latin terms obviously helped create the bookkeeping abbreviations (Dr.) and (Cr.) as well. This is because there is no ‘r’ in the English word Debit but there is one in the Latin term 'Debere'.
In Latin, the term ‘Credre’ means to entrust something and ‘Debere’ means to owe someone. For example, if Person (A) entrusts $100 to Person (B) then Person (B) owes $100 to Person (A) immediately. The example also shows that financial transactions always have two sides to them and that money received by a business must come from someone who has entrusted it. Using the terms ‘Credre’ and ‘Debere’, Friar-Luca was able to describe this principle of two sides to every financial transaction.
He called entries on the left side of the ledger's ‘T’ accounts, Debits, and entries on the right hand side of the ledger's ‘T’ account, Credits. He was so convinced of the duality of financial transactions he declared that no bookkeeper should go to sleep at night unless the total of the (Dr.-Debit) equalled the total of the (Cr.-Credit).
‘(Dr.-Debit) and (Cr.-Credit)’ in the bookkeeping system is simply a method of classification which provides a way of recording the changing values in the financial accounts of a business caused by monetary transactions. At the same time, the ‘(Dr.-Debit) and (Cr.-Credit)’ method of classification keeps the accounting equation always in balance, i.e. Assets = Liabilities + Owners Equity.