Domain Name Service: DNS:
This term is MUCH less complicated than it sounds.
It’s the service that keeps track of all the Domain Names on the planet. Think of your domain name sort of like your phone number, only easier for people to remember. Those letters resolve to a number, called an IP address. Of course, since the Internet is world wide, there can only be ONE of each domain name anywhere on earth. The DNS keeps track of where that domain’s website is living (what server it’s on).
We use the term kind of loosely when we say “Change the DNS” meaning that we’re going to tell the Internet where your website is hosted.