The NS, or Name Server records of a domain, reveal which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a given hosting provider for your domain name is the most effective way to point 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), etc, so if you need to change any of these records, you will be able to do it through their system. In other words, the NS records of a domain name show the DNS servers that are authoritative for it, so when you try to open a web address, the DNS servers are contacted to obtain the DNS records of the domain you are attempting to reach. That way the web site that you will see is going to be retrieved from the proper location. The name servers usually have a prefix “ns” or “dns” and each domain name has at least 2 NS records. There's no functional difference between the two prefixes, so what kind a web hosting provider is going to use depends entirely on their preference.