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 most convenient way to forward 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), etc, if you need to modify any of these records, you'll be able to do it via their system. Put simply, the NS records of a domain address point out the DNS servers which 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 want to reach. This way the site that you'll see will be retrieved from the correct location. The name servers typically have a prefix “ns” or “dns” and each domain name has at least 2 NS records. There is absolutely no functional difference between the two prefixes, so which one a website hosting provider is going to use depends only on their preference.