Net receivables, also called accounts receivable, is the money customers owe for things they bought on credit, sold and booked as revenue, but not yet paid for. That gap is the key to understanding it: accounting counts the sale the moment it happens, so revenue can look great while the cash still sits in customers' hands. The "net" means the company has already subtracted its own estimate of bills that will never be paid.
What to watch: receivables growing much faster than revenue, which means sales are being made but cash is not following, whether from struggling customers, over-generous payment terms used to juice sales, or worse (see channel stuffing).