a list of people who have asked for something that is not immediately available but will be in the future

The hospital has a two-year waiting list for minor operations. 这家医院的小手术已经排到了两年后。

The course is full, but I can put you on the waiting list, in case someone drops out. 这门课程已经满员了，但我可以把你列在等候名单里，说不定有人会放弃。