A: The book I want to buy is a back order and won’t be shipped for three weeks.

B: Why don’t you just buy a Kindle version?

A: Because there is no Kindle version yet.

Note: This term refers to “a business order yet to be fulfilled because stock is unavailable.” The word first appeared in the late 19th century. It can be also used as a verb, meaning “to assign to the status of back order.” The percentage of items back-ordered and the number of back order days are important measures of the quality of a company’s customer service and the effectiveness of its inventory management.