DNS is Domain Naming System (some say Domain Name Services) and is a foundational building block of the internet.
In it’s simplest form, it is a lookup tool. A way to resolve names to IP addresses. Remember when we used phone books? If you knew your friend Bob lived on Main St., using his name and address you could look up his phone number. This is kind of how DNS functions.
When you want to read news you might type in cnn.com into your web browser, but cnn.com is really an IP address and for your computer to be able to pull that site up, it needs to have a way to resolve that name to a number. Your computer “looks up” cnn.com in the “phone book” and returns that web site via the browser.
That’s a really incomplete, super high level view of it, and DNS does a lot of more than just resolve web site names and addresses, but it’s nice to understand that there is a mechanism by which that resolution takes place.
I’m not a mechanic by any means, but I have a basic understanding of internal combustion engines that is sufficient for me to understand what my mechanic is telling me when something is wrong with my car. Similarly, having an understanding of how information gets from the internet back to your computer can sometimes be enabling or make us better users of the technology in the world around us. If not better, at least maybe a little more infomred. And sometimes informed is enough.