The NS, or Name Server records of a domain, point out which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a specific hosting provider for your domain name is the most effective way to direct 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), etc, so if you would like to change any one of these records, you're going to be able to do it via their system. To put it differently, the NS records of a domain address point out 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 Internet domain you are attempting to access. In this way the website you will see will be retrieved from the right location. The name servers usually have a prefix “ns” or “dns” and each and every domain name has at least two NS records. There's no practical difference between the two prefixes, so which one a website hosting provider will use depends exclusively on their preference.