Online Public Access Catalog (OPAC) is an essential tool for libraries that offers patrons access to the library's resources. The term OPAC is widely used in libraries, especially academic and public libraries. However, other synonyms for OPAC include online library catalog, online catalog, digital library catalog, electronic library catalog, and virtual library catalog. These alternative terms refer to the same system that allows library users to search, locate, and request books and other materials online. Despite the different names, the function of the OPAC remains the same, providing a platform for easy access to library resources.