A DNS lookup is the process of translating a human-readable domain name, like www.example.com, into its corresponding numerical IP address, such as 192.0.2.1. This translation is essential because computers and network devices use IP addresses to identify and communicate with each other on the internet. When you enter a website address into your browser, your device queries a DNS server to find the correct IP address. If the DNS server has the information cached, it responds immediately; otherwise, it forwards the request to other servers. DNS lookups are fundamental to internet browsing and are often targeted in cybersecurity attacks like DNS spoofing or poisoning.