If your here, you probably asking, “What is a Name Server, and why do I need this wierd looking thing to make my site work? More so why should I care?”
A Name Server is a couple of DNS records that tell your domain where its ZONE/Host file is. Think of it as the clerk at the store who points you to the map for your trip. You need to locate the map befor you can locate your destination. In this case your website, and your email!
Where ever you point your Name Servers to is where the map of where and how your domain goes, is.
Here is a visual example of what that would look like if the internet existed in the real world: