A debit is a financial transaction that reduces the balance in a bank account. When you use a debit card to make a purchase, the money is directly taken from your checking account. This means you can only spend what you have, helping to avoid debt. In accounting, a debit entry increases assets or expenses and decreases liabilities or equity. For example, when a business buys supplies, it records a debit to the supplies account, reflecting an increase in assets. This system helps maintain accurate financial records and ensures proper tracking of a company's finances.