What does "pigeonhole" commonly refer to?

The term "pigeonhole" commonly refers to a storage compartment for letters or documents. This term derives from the way these compartments are designed to hold correspondence in an organized manner, similar to how pigeonholes were originally used to house birds. In an office setting, pigeonhole arrangements allow for easy sorting and retrieval of documents or mail, making it easy to distribute items to various individuals or departments.

While a large file cabinet and a box used for sorting might serve similar functions, they do not capture the specific arrangement and purpose implied by the term "pigeonhole." Additionally, while sorting documents is a related concept, it doesn’t define the actual structure referred to as a pigeonhole.