Definition, synonyms and related words
An order that cannot be currently filled or shipped, but is requested nonetheless for when the item becomes available again.
"After checking the stock levels, the salesperson explained that the popular headphones were on backorder and would ship automatically once new inventory arrived next month."
To place such an order
"When I called to check on my purchase, the agent confirmed that my request was placed as a backorder because the item was out of stock."