Chart of Accounts
Every accounting transaction is made to an Account. Every category of Expense, Income, debt (liability) and Equity (net worth) has a name and a unique number. Each of these categories, named and numbered by the accountant, is called an Account. For example "80000-Rent" and "10100-Cash in Bank" are a typical Accounts. A complete list of Accounts is called the Chart of Accounts.
So, the question is asked, "Are numbers necessary for Accounts?" They are probably not absolutely necessary, but they make life a lot easier. Numbers are very useful in quickly discerning whether an Account is an Asset, a Liability, Income or an Expense. Second, numbers are used to place accounts in a certain sequence on the Balance Sheet and Income Statement. This helps maintain order. Numbering makes it easier, so numbering is part of the accounting program.