A wide area network (WAN) is a telecommunications network that extends over a large geographical area, connecting multiple local area networks (LANs). WANs are commonly used by businesses and organizations to facilitate communication and data sharing between offices located in different cities or countries. WANs utilize various transmission technologies, such as fiber optics, satellite, and wireless connections, to transmit data over long distances. They can be privately owned or leased from service providers, allowing users to access the internet and share resources efficiently across vast areas.