LAN, Local-Area Network, is a computer network spread over a relatively small area. Often, a LAN is limited to a single flat, building, or group of buildings. However, a LAN can be connected to other LANs at any distance via telephone lines and radio waves.

Most LANs connect workstations and personal computers. Each node (personal computer) in a LAN has its own CPU where it executes programs, but can also access data and devices from anywhere on the LAN. This means that many users have printers etc. means it can share devices and data. Users can also use LAN to communicate with each other by sending emails or joining chat sessions.

LANs can transmit data at much higher rates than can be transmitted over a telephone line. However, distances are limited and there is also a limit to the number of computers that can be connected to a single LAN.