A hole for pigeons.

鸽笼。

A small, open, boxlike space in a desk, case, etc. for documents, letters, or the like.

(写字台上或箱盒中用以致书信文件等的)鸽笼式分类架。

To place, as letters, in such a boxlike space.

置于分类架内。

To lay aside and forget.

搁置；束之高阁。

To assign to a definite place.

分类保存((for))。