A trial balance is a proof of accuracy of double entry in the ledger. Double entry means that for every transaction recorded in the ledger, there should be at least two accounts affected - a debit account and a credit account. A trial balance is a list of all the account balances in the ledger, separated by their respective debit or credit sides. The total of all debit balances should be equal to the total of all credit balances. If they are not equal, it indicates that there is an error in the double entry, and the trial balance is said to be "unbalanced". Therefore, a balanced trial balance is an indication that all the transactions recorded in the ledger have been accurately entered in the appropriate accounts, thus serving as a proof of accuracy of double entry in the ledger.