Operating cash flow
The cash a company's day-to-day business brings in during a period. It starts from net income, adds back non-cash costs such as depreciation, and adjusts for cash tied up in or released from working capital.
Simple example
A company has $50 of net income and $20 of depreciation, and $10 more is tied up in unpaid customer invoices. Its operating cash flow is $50 + $20 − $10 = $60.