The NS, or Name Server records of a domain name, show which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain 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 forth, if you need to change any one of these records, you will be able to do it through their system. Put simply, the NS records of a domain reveal the DNS servers that 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 you will see is going to be retrieved from the correct location. The name servers typically have a prefix “ns” or “dns” and each domain has at least two NS records. There isn't any sensible difference between the two prefixes, so what kind a host company will use depends exclusively on their preference.