turnover in a financial context refers to the rate at which a provider of goods cycles through its average inventory. The number of times within its business cycle that a company completely exhausts (and replenishes) its inventory is called its turnover. Auditors will frequenlty use a company's turnover ratio (turnover = cost of goods sold/average inventory level) to compare it to other companies in its industry.
This may not apply to a non-profit making business of course where other factors are important, such as gross rents on a Housing Association , and service charges.
Fee income for an accounatant/solicitor.
Don't just think business means 'sales' as there is more business that is not just sales ,but fees earned for labour supplied.