The word 图书馆 (túshūguǎn, "library") is formed by combining three meaningful characters into a single conceptual unit. It builds logically from its parts: 图 (tú) means "diagram" or "picture", 书 (shū) means "book", and 馆 (guǎn) means "building" or "hall". Thus, the compound visually and conceptually progresses from "pictures" to "books" to the "building" that houses them, ultimately creating the modern idea of a repository for books and other materials of knowledge and reference.