Accounting uses accounts to sum up activity related to a particular function of business. As an example the bank account has a register which identifies the activity in a ledger format of what transpires at the bank for this particular account.
Within the chart of accounts exist control accounts which use subsidiary accounts to track information related to a particular function of business. Good examples include Account Receivables and Account Payables which function as control accounts. Customer identification is used to track the different customers and vendors which act as the subsidiary accounts.