The NS, or Name Server records of a domain name, show which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a given host company for your domain is the simplest way to point it to their system and all its sub-records will be taken care of 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, so if you wish to modify some of these records, you are going to be able to do it through their system. In other words, the NS records of a domain 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 get the DNS records of the domain name you are attempting to reach. This way the web site you'll see is going to be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and every single domain has at least two NS records. There is no functional difference between the two prefixes, so which one a host company will use depends solely on their preference.