A more thorough explanation:

Definition: A book or series of books used for recording financial transactions in the form of debits and credits. It can also refer to a resident ambassador or agent.

• My accountant keeps a leger to track all of my business expenses and income.
• The company's general leger showed a significant increase in profits this quarter.
• The leger of the ambassador's activities was closely monitored by the government.

The first two examples illustrate the use of leger as a financial record-keeping tool. The leger is used to keep track of all financial transactions, including debits and credits. The third example illustrates the archaic use of leger as a resident ambassador or agent.