The NS, or Name Server records of a domain, show which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a specific hosting provider for your domain address is the most effective way to forward 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 if you need to edit any one of these records, you'll be able to do it using their system. In other words, the NS records of a domain show the DNS servers that are authoritative for it, so when you try to open a web address, the DNS servers are contacted to retrieve the DNS records of the Internet domain you are trying to access. That way the website that you will see will be retrieved from the correct location. The name servers usually have a prefix “ns” or “dns” and every single domain address has at least two NS records. There isn't any practical difference between the two prefixes, so which one a hosting provider is going to use depends only on their preference.