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 hosting provider for your domain name is the simplest way to direct it to their system and all its sub-records will be taken care of 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, in case you need to change some of these records, you will be able to do it via their system. To put it differently, the NS records of a domain name show the DNS servers that are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to retrieve the DNS records of the domain you are attempting to reach. That way the web site you will see is going to be retrieved from the right location. The name servers typically have a prefix “ns” or “dns” and each and every domain address has at least 2 NS records. There's no practical difference between the two prefixes, so what kind a host company will use depends only on their preference.