The NS, or Name Server records of a domain name, reveal which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain name is the most effective 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), etcetera, so, in case you would like to modify any one of these records, you will be able to do it by using their system. In other words, the NS records of a domain point out the DNS servers which 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 Internet domain you are attempting to access. This way the site that you're going to see is going to be retrieved from the proper location. The name servers normally have a prefix “ns” or “dns” and every single domain has at least 2 NS records. There's no sensible difference between the two prefixes, so what kind a host company will use depends exclusively on their preference.