The NS, or Name Server records of a domain name, reveal which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain address is the easiest way to direct it to their system and all its sub-records are going to be managed on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), etc, if you wish to edit any one of these records, you will be able to do it using their system. In other words, the NS records of a domain show the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to retrieve the DNS records of the domain name you want to reach. That way the web site that you'll see is going to be retrieved from the proper location. The name servers typically have a prefix “ns” or “dns” and every single domain name has at least 2 NS records. There's no functional difference between the two prefixes, so which one a web hosting provider will use depends entirely on their preference.