The NS, or Name Server records of a domain name, 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 is the most effective way to forward 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), and so on, if you wish to change any one of these records, you'll be able to do it through their system. In other words, the NS records of a domain address point out 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 you are trying to reach. That way the web site you will see will be retrieved from the right location. The name servers normally have a prefix “ns” or “dns” and each domain address has at least two NS records. There isn't any functional difference between the two prefixes, so which one a web hosting provider is going to use depends entirely on their preference.