Explain Like I'm Five

DNS = Domain Name System

Computers talk in computer language. When they need to contact one another, they use an address to find each other, like we use addresses to find our homes or businesses on a map. Theirs is called an IP address, or Internet Protocol address. It's a series of numbers (and sometimes letters) that computers recognize as an address on the Internet.

But to humans, IP addresses are complex jumbles of numbers and letters. If you want to go to Google's website, you might type in one of their many IP addresses (e.g. 216.58.198.46, or 2a00:1450:400e:808::200e), but how are you ever going to remember all that nonsense? And for every single individual website?!

Instead, you can remember a simple little URL, or Uniform Resource Locator, that's quick and easy to recall: google.com.

DNS is a process that keeps track of all IP addresses and their associated hostnames (or URLs) and will translate between the two of them on the fly. For example, you tell your computer you want to go to amazon.com and DNS will tell the computer to track down 98.82.161.185.

TL;DR - DNS translates between human web addresses and computer web addresses, so us humans can communicate with our computers and receive information from across the Internet.

Bonus: Google secured a very simple IP address long ago, so even humans can remember how to find them: 8.8.8.8. I worked in an IT field for 20 years, managing a DNS server (along with dozens of other servers and thousands of personal computers). If the DNS server ever went down, we'd use that simple IP address to get to Google's website so we could search for answers while troubleshooting. To this day, it's the only public IP address I still remember.