The NS, or Name Server records of a domain name, point out which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain address is the easiest 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), etcetera, so, in case you want to change some of these records, you'll be able to do it via their system. Put simply, 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 get the DNS records of the domain you are attempting to reach. In this way the website that you will see is going to be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and each and every domain has at least two NS records. There is absolutely no functional difference between the two prefixes, so what kind a host company will use depends only on their preference.