The NS, or Name Server records of a domain, indicate which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a particular hosting provider for your domain is the easiest way to point it to their system and all its sub-records will be managed on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), etc, if you want to edit any of these records, you will be able to do it using their system. To put it differently, the NS records of a domain point out the DNS servers that are authoritative for it, so when you try to open a web address, the DNS servers are contacted to obtain the DNS records of the Internet domain you are attempting to reach. In this way the site you will see will be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and each and every domain address has at least two NS records. There's no sensible difference between the two prefixes, so which one a host company will use depends only on their preference.