A domain name can be used to host a web site (such as www.actrix.co.nz) or create customised E-mail addresses (such as firstname.lastname@example.org) and is basically a human language representation of an IP address.
What's an IP Address you ask? An IP Address is what every computer on the internet uses to address itself to the other computers on the Internet (using the network protocol called TCP/IP. IP (v4) Addresses look like 18.104.22.168.
When someone types in a domain name like www.actrix.co.nz, their browser communicates with a series of root domain name servers that act as a dictionary and provide the IP address associated with that domain name. Then the browser can use that IP to communicate with the server that the website is hosted on.
If you are planning on purchasing a domain (or already own one) there are a few technical terms you may want to understand which could make life easier when requesting changes or identifying problems.
Domain Name Registrar is the company used to register a domain. I.e. A customer (the registrant) contacts Actrix (the registrar) to register mydomain.co.nz.
Domain Name Registrant is the person defined as having registered and who owns a domain. I.e. A customer (the registrant) contacts Actrix (the registrar) to register mydomain.co.nz.
A-Records (or Address Record) is the basic and most important DNS (Domain Name System) record. A-records point to an IP address. Your short domain name (without the www), NS (Name Server), and FTP (File Transfer Protocol) should have A-records. Subdomains sometimes have A-Records too. A-records can point to any IP-address.
CNAME-Records (or Canonical Domains) include subdomains and Aliases, CNAMEs are used to point to a domain name or to a file in a domain. However, CNAMEs should always point to an A-record, not another CNAME. It is a common practice to create a CNAME for www and for subdomains that are actually hosted by your domain. CNAMES can also be used as temporary aliases to point your domain to another domain.
MX-Records (or Mail Exchange) point to the name of an email server and hold a preference number for that server. MX-records must point to an A-record or in some situations an IP-address.
FTP (File Transfer Protocol) is used to transfer data from one computer to another over the Internet, or through a network. The FTP server, running FTP server software, listens on the network for connection requests from other computers. The client computer, running FTP client software, initiates a connection to the server. Once connected, the client can do a number of file manipulation operations such as uploading files to the server, download files from the server, rename or delete files on the server and so on.
There are various types of domain names such as .co.nz, .com, .org.nz, .net.nz, etc. Domains that end in .nz are local to New Zealand and are generally cheaper to purchase, domains without a country code such as .com are considered international domains and generally cost a bit more.