What is a Domain Name?

New computer users often confuse domain names with universal resource locators, or URLs, and Internet Protocol, or IP, addresses. This confusion is understandable. It is worth learning the differences between them because these terms are ubiquitous. It is also helpful to be able to use terms correctly when communicating to technicians or other people within a professional organization.
This naming convention is analogous to a physical address system. People find web pages in a manner similar to the way that they use maps to find physical locations. If the Internet is like a phone book, and a web page is like a physical building, the URL would be the precise street address of that building. The IP address would be like the car that travels to its destination. There are also other useful metaphors for understanding this relationship.

Domain Names and URLs

The universal resource locator, or URL, is an entire set of directions, and it contains extremely detailed information. The domain name is one of the pieces inside of a URL. It is also the most easily recognized part of the entire address.
When computer users type a web address directly into the field at the top of their browser window, it initiates a process of locating the page requested. To do so, the instructions contained inside the URL, including the domain name, must correctly point to that location. The IP address is a numerical code that makes this possible.

Domain Names and IP Addresses

An Internet Protocol, or IP, address is different than a domain name. The IP address is an actual set of numerical instructions. It communicates exact information about the address in a way that is useful to the computer but makes no sense to humans. The domain name functions as a link to the IP address. Links do not contain actual information, but they do point to the place where the IP address information resides. It is convenient to think of IP addresses as the actual code and the domain name as a nickname for that code. A typical IP address looks like a string of numbers. It could be 232.17.43.22, for example. However, humans cannot understand or use that code. To summarize, the domain name is a part of the URL, which points to the IP address.

What's in a Domain Name?

 

Domain names function on the Internet in a manner similar to a physical address in the physical world. Each part of the domain name provides specific information. These pieces of information enable web browsers to locate the web page. The naming system is closely regulated in order to prevent confusion or duplicate addresses. As demand increased exponentially, a new Internet Protocol version, or IPv6, was created to expand the amount of domain names available.

How do Domains Work?

Domain names work because they provide computer users with a short name that is easy to remember. Users enter web addresses into the URL field at the top of their browser's page from left to right. The domain name itself is read from right to left according to the naming hierarchy discussed below. This link provides directions to the network, which ultimately results in a successful page load at the client end of the transaction.
The common fictitious domain name, www.example.com, is comprised of three essential parts:

• .com - This is the top-level domain.
• .example. - This is a sub-domain.
• www. - This is a sub-domain prefix for the World Wide Web. The original use of this prefix was partly accidental, and pronunciation difficulties raised interest in creating viable alternatives.

Many servers use a three-letter naming convention for top-level domains, and they are separated from sub-domains by a dot. The significance of the top-level domain is the most important for new users to grasp. It identifies the highest part of the naming system used on the Internet. This naming system was originally created to identify countries and organizations as well as categories.
The most common categories are easily recognized by new computer users, and they include:

• .com
• .org
• .edu
• .net
• .mil

A significant expansion of the top-level domains occurred, and they now include:

• .biz
• .museum
• .info
• .name

Country codes are also easily recognizable to new users because the abbreviations are the same ones used for other purposes. The organization of the domain name hierarchy and the ability to reserve them for only one purpose has already undergone several modifications. Discussions and debates concerning the availability and affordability of domain names can be expected to continue.
Sub-domains are organized to the left of the top-level domain, and this is the part of the domain system that is most recognizable to humans. It is common to see several levels of sub-domains, and some countries developed specific conventions of organization to communicate information within their internal naming systems.
Source:whatismyipaddress