A catalog is a systematic list or collection of items, often organized for easy reference. It can include products, services, or resources, and is commonly used by businesses, libraries, and educational institutions. Catalogs help users find specific items quickly and efficiently, often providing details like descriptions, prices, and availability. There are various types of catalogs, such as product catalogs for retail businesses, library catalogs for books and media, and online catalogs for digital resources. They can be printed or available online, making it convenient for users to access information from anywhere at any time.