The NS, or Name Server records of a domain, point out which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain address is the most convenient way to direct 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), etcetera, so if you want to change any one of these records, you'll be able to do it via their system. In other words, the NS records of a domain name reveal the DNS servers which 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 access. In this way the web site you will see is going to be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and each domain name has at least 2 NS records. There is no practical difference between the two prefixes, so what kind a website hosting provider is going to use depends entirely on their preference.