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 host company for your domain is the most convenient 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), etcetera, if you would like to edit some of these records, you are going to be able to do it via their system. Put simply, the NS records of a domain name reveal 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 want to access. This way the site that you're going to see is going to be retrieved from the correct location. The name servers normally have a prefix “ns” or “dns” and each domain has at least 2 NS records. There is no functional difference between the two prefixes, so what type a hosting provider is going to use depends solely on their preference.