A shelf is a flat surface that is usually attached to a wall or part of a piece of furniture. It is used to hold various items, such as books, decorations, or kitchenware. Shelves come in different sizes and materials, like wood or metal, and can be found in homes, offices, and stores. They help keep spaces organized and make it easy to access items. In a library, for example, books are arranged on shelves for easy browsing. A bookshelf is a specific type of shelf designed to hold books, while a kitchen shelf might hold spices or dishes. Shelves are essential for maximizing storage and keeping things tidy.