The Domain Name System (DNS) plays a critical role in the Internet infrastructure by translating human-readable domain names (like www.example.com) into IP addresses that computers use to identify each other. DNS functions as a distributed directory, facilitating the routing of Internet traffic effectively and efficiently. It enhances user experience by allowing access to websites without memorizing complex numeric addresses. Furthermore, it contributes to security measures like DNSSEC, ensuring data integrity in the translation process.