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 particular hosting provider for your domain address is the simplest way to point 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, so if you want to modify some of these records, you will be able to do it through their system. In other words, the NS records of a domain name show the DNS servers which are authoritative for it, so when you try to open a web address, the DNS servers are contacted to get the DNS records of the domain you are attempting 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 and every domain name has at least 2 NS records. There's no practical difference between the two prefixes, so what kind a hosting provider will use depends completely on their preference.