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 hosting provider for your domain name is the easiest way to point it to their system and all its sub-records are going to be handled 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, so, in case you would like to edit some of these records, you're going to be able to do it through their system. To put it differently, the NS records of a domain address show 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 Internet domain you are attempting to access. That way the website that you'll see will be retrieved from the correct location. The name servers typically have a prefix “ns” or “dns” and every single domain has at least 2 NS records. There's no functional difference between the two prefixes, so what type a hosting provider is going to use depends completely on their preference.