one of a set of small boxes, open at the front, in which letters and messages are left for different people

Leave the report in my pigeonhole when you've read it. 你看完后把报告放在我的分类架里。

put something/someone in a pigeonholeidiom usually disapproving 想当然地把…归类

to have an often unfair idea of what type someone or something is

He is a film producer who can't be conveniently pigeonholed. 他是个电影制片人，不能把他简单地归于哪一类。

to put something away or leave it until a later time

Consultants found the experience frustrating - their reports were only partly implemented, or, worse still, just pigeonholed. 顾问们感到相当沮丧——他们的报告只是被部分实施，或更糟糕地只是束之高阁。