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 host company for your domain is the most effective way to point 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, if you want to change any of these records, you're going to be able to do it by using 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 retrieve the DNS records of the domain name you are trying to access. This way the site that you will see will be retrieved from the proper location. The name servers usually have a prefix “ns” or “dns” and every single domain has at least 2 NS records. There is no sensible difference between the two prefixes, so what type a website hosting provider will use depends exclusively on their preference.