Order Backlog
Orders for goods or services that have not yet been fulfilled. They can be measured in cash terms, or by the number of days of normal production it would take to clear them. The level of backlogs is an important indicator of whether an economy is growing or not. Falling backlogs may be a sign that new orders are dropping and the old ones are being fulfilled, and that producers are less willing to hold large stocks or inventories.
See also: Economic Indicator