The NS, or Name Server records of a domain name, indicate which servers handle 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 will be taken care of 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, in case you wish to change some of these records, you will be able to do it through their system. Put simply, the NS records of a domain address show 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 are attempting to reach. That way the website you will see is going to be retrieved from the proper location. The name servers usually have a prefix “ns” or “dns” and every single domain name has at least two NS records. There's no functional difference between the two prefixes, so what kind a host company is going to use depends completely on their preference.