The main function of the Domain Name System (DNS) is to translate human-readable domain names into IP addresses, which are used by computers to identify and communicate with each other on the Internet. DNS acts as a directory for the web, allowing users to access websites using easy-to-remember names like www.example.com instead of numeric IP addresses. This system enhances the usability of the Internet by streamlining the process of locating resources and is essential for maintaining the overall functionality of the web.