Name Servers, or Authoritative Name Servers, are as the name implies, the "name of the server", and it's the most important DNS setting on the domain, as they are responsible for setting the DNS Zone and returning DNS Records queries.
This means that Name Servers indicate where your DNS settings are managed, and where you should add or remove records.
Name Servers always come in pairs (at a minimum), and you can have up to 6 Name Servers at Epik. They often appear with a descriptive subdomain hostname such as:
Note that changing the domain's Name Servers must be done at the domain's registrar.