1680s, "large log placed at the back of a fire," from back (adj.) + log (n.1). Figurative sense of "something stored up for later use" is first attested 1883, but this and the meaning "arrears of unfulfilled orders" (1932) might be from, or suggested by, log (n.2).
权威例句
1. There is a backlog of repairs and maintenance in schools.
对各学校的修缮和维护工作积压了一堆。
2. We are faced with a backlog of orders we can't deal with.