The NS, or Name Server records of a domain, show which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a given hosting provider for your domain name is the most convenient way to forward it to their system and all its sub-records are going to 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), and so on, if you would like to change some of these records, you're going to be able to do it through their system. In other words, the NS records of a domain show 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 Internet domain you are trying to access. This way the site that you will see will be retrieved from the right location. The name servers usually have a prefix “ns” or “dns” and each domain has at least 2 NS records. There is absolutely no functional difference between the two prefixes, so which one a website hosting provider will use depends solely on their preference.