The phrase "to open an account" means to establish a new financial or non-financial record, usually with a company or institution. This can refer to opening a bank account, brokerage account, credit card account, utility account, membership account, etc., where one creates and maintains a record of transactions, balances, payments, etc. It also refers to starting a new record or log for something such as time, mileage, expenses, etc. In essence, it means initiating a new relationship with an organization by creating a unique identification number or username that allows access and tracking of activities within the account.