DDC stands for Dewey Decimal Classification. It is a widely used library classification system that was developed by Melvil Dewey in the late 19th century. The DDC is based on a hierarchical structure, with 10 main classes at the top and more specific categories and subcategories below them. Each class, category, and subcategory is assigned a unique decimal number, which is used to identify and locate materials within the classification system.
The DDC is used in libraries around the world to organize and classify books and other materials according to subject matter. It is particularly popular in public libraries and school libraries, as it is relatively easy to use and understand. The DDC is regularly updated and revised to reflect changes in knowledge and subject matter, and it is considered to be an essential tool for organizing and accessing information in libraries.