The NS, or Name Server records of a domain, show which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain name is the most convenient way to forward it to their system and all its sub-records will 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 forth, if you want to modify any of these records, you are going to be able to do it through their system. To put it differently, the NS records of a domain name point out the DNS servers that 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 name you want to access. That way the site that you'll see is going to be retrieved from the correct location. The name servers usually have a prefix “ns” or “dns” and each domain has at least 2 NS records. There's no practical difference between the two prefixes, so which one a hosting provider is going to use depends exclusively on their preference.