The NS, or Name Server records of a domain, point out which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a specific hosting provider for your domain is the most convenient way to direct it to their system and all its sub-records will 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), etcetera, if you would like to edit any of these records, you're going to be able to do it by using their system. Put simply, the NS records of a domain reveal the DNS servers which are authoritative for it, so when you try to open a web address, the DNS servers are contacted to retrieve the DNS records of the domain name you are trying to access. That way the website you'll see is going to be retrieved from the proper location. The name servers normally have a prefix “ns” or “dns” and each and every domain address has at least two NS records. There's no sensible difference between the two prefixes, so what kind a hosting provider is going to use depends entirely on their preference.