The NS, or Name Server records of a domain, reveal which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a particular hosting provider for your domain address is the simplest way to forward 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 on, if you wish to modify any of these records, you'll be able to do it by using their system. In other words, the NS records of a domain show the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to obtain the DNS records of the domain name you are trying to access. In this way the web site that you will see will be retrieved from the right location. The name servers normally have a prefix “ns” or “dns” and every single domain address has at least 2 NS records. There isn't any functional difference between the two prefixes, so what kind a website hosting provider will use depends exclusively on their preference.