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 is the simplest way to point 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), and so on, so, in case you would like to edit any one of these records, you are going to be able to do it through their system. In other words, the NS records of a domain point out the DNS servers that 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 domain name you are attempting to access. That way the site that you'll see will be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and each and every domain has at least 2 NS records. There is no sensible difference between the two prefixes, so what kind a website hosting provider will use depends solely on their preference.