Simply put, a Domain Name System (DNS) is a collection of databases that translate hostnames into IP addresses.

DNS is often called the phone book of the Internet because it translates easy-to-remember hostnames like www.google.com into IP addresses like 216.58.217.46. This happens behind the scenes after you type a URL into the address bar of a web browser.

Without DNS (and especially search engines like Google) it would not be easy to surf the internet, because we would have to type in the IP address of every website we wanted to visit.

If it's still not clear, the basic concept of how DNS does its work is pretty simple: Any web address entered into a web browser (like Chrome or Firefox) is sent to a DNS server, which knows how to match that name to the correct IP address.