The NS, or Name Server records of a domain name, indicate which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a specific hosting provider for your domain name is the most convenient way to direct it to their system and all its sub-records are going to be handled on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), and so on, so if you need to edit any of these records, you will be able to do it via their system. Put simply, the NS records of a domain address show the DNS servers which are authoritative for it, so when you try to open a web address, the DNS servers are contacted to get the DNS records of the Internet domain you want to access. This way the web site that you'll see will be retrieved from the proper location. The name servers normally have a prefix “ns” or “dns” and every single domain address has at least two NS records. There's no functional difference between the two prefixes, so what type a website hosting provider is going to use depends only on their preference.