The NS, or Name Server records of a domain name, show which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a given host company for your domain name is the simplest 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, so, in case you need to edit any one of these records, you're going to be able to do it via their system. In other words, the NS records of a domain reveal the DNS servers that are authoritative for it, so when you try to open a web address, the DNS servers are contacted to retrieve the DNS records of the Internet domain you are trying to reach. That way the web site that you're going to 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's no sensible difference between the two prefixes, so which one a host company is going to use depends solely on their preference.