The NS, or Name Server records of a domain, indicate which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a specific host company for your domain address is the easiest way to point 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), etc, if you would like to change any one of these records, you're going to be able to do it by using their system. To put it differently, the NS records of a domain address reveal 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 Internet domain you want to access. In this way the site that you will see will 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 isn't any sensible difference between the two prefixes, so what kind a hosting provider will use depends exclusively on their preference.