NETWORK

A network is a group of two or more computer systems linked together. There are many types of computer networks, including:

Local area networks (LAN) : The computers are geographically close together (that is, in the same building). such as a building or an office. 

Wide area networks (WAN) : The computers are farther apart and are connected by telephone lines or radio waves.

Campus area networks (CAN): The computers are within a limited geographic area, such as a campus or military base and so on.

Metropolitan area networks (MAN): A data network designed for a town or city.

Home area networks (HAN): A network contained within a user's home that connects a person's digital devices.