What is 本?

本 (Hěn) is a Chinese counter word, often used for bound objects such as:

• Books: Used to count physical books, notebooks, and dictionaries. https://www.wikiwhat.page/kavramlar/books
• Magazines: Counts periodicals and journals.
• Documents: Can refer to bound collections of papers, reports, or files.
• Collections: Can even refer to things like a collection of photographs, if they are bound together.

Essentially, it's used for things that are bound or have a book-like form. The most common use is for counting books.