When you buy hosting you will also be provided with information about your nameservers. These look like an email address, and are usually a sequence of letters and numbers, followed by your host’s site name, for example, “firstname.lastname@example.org” Keep this information safely!
The technical definition of a nameserver is, according to WikiPedia, “a computer server that hosts a network service for providing responses to queries against a directory service. It maps a human-recognizable identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a network service protocol request.”
So, nameservers are the actual location assigned to your site on the servers of your host. For now save the email and make a note of the information!