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 given hosting provider for your domain address 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 forth, so, in case you want to modify some of these records, you'll be able to do it using their system. In other words, the NS records of a domain name reveal the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to obtain the DNS records of the domain you want to reach. This way the website that you'll see is going to be retrieved from the proper location. The name servers usually have a prefix “ns” or “dns” and each domain has at least two NS records. There is absolutely no functional difference between the two prefixes, so what kind a hosting provider will use depends exclusively on their preference.