Definition
Local Area Network (LAN):
It is a computer network <http://en.wikipedia.org/wiki/Computer_network> covering a small geographic area, like a home, office or group of buildings, e.g., a school. The defining characteristics of LANs, in contrast to wide-area networks (WANs) <http://en.wikipedia.org/wiki/Wide-area_network>, include their much higher data-transfer rates, smaller geographic range, and lack of a need for leased telecommunication lines <http://en.wikipedia.org/wiki/Leased_line>