What is a computer network?
Before defining computer network, let’s first look at the general term of a network in order to then recognize the computer network definition in particular. If you do a search for the word network in the Merriam-Webster dictionary, you’ll find the definition that a "network is a group of people or organizations that are closely linked and that work with each other." On the same Merriam-Webster dictionary, the phrase networking is defined as "exchange of information or services among individuals, groups or institutions." Both of these definitions will serve us in a simple, clear, and concrete way to define computer network in the following paragraph.
From what was said in the preceding paragraph, a computer network is a group of computers connected to each other in order to share resources. When talking about resources, usually the resources can be data, network services, and peripheral devices. So, anyone who has experience with computer networks has seen that it is very easy to share files, applications, printers, and other peripheral devices in computer networks. Figure 1.1 presents an example of a computer network:

Figure 1.1. Computer network
Note
You can learn more about computer networks at https://www.computerhope.com/jargon/n/network.htm.
Requirements for designing a computer network
Of course, the most beautiful part of a computer network is how to design and build one. Computer network design and deployment is Designing and deploying is linked to its definition. Thus, the fundamental requirement for designing a computer network is that there must be two or more computers. Depending on the number of computers on the network and how they access the resources from the same network determines the categorization of computer network types, which will be explained in the following section.