to back order
01
预订等待, 预留订购
to request or take an order for a product that is not currently in stock, to be delivered when it becomes available
例子
They back-ordered the book and received it a week later.
他们预购了这本书，一周后收到了它。
Back order
01
缺货订单，补货中
a situation where a product is temporarily out of stock but can be ordered for future delivery
例子
Due to high demand, the product is frequently on back order.
由于需求旺盛，该产品经常处于缺货预订状态。
