Local Area Network
A Local Area Network (LAN) is a network that usually consists of a relatively small amount of computers or devices. The LAN facilitates digital connections between the nodes and often times provides an uplink to a MAN, WAN or to the Internet.
LANs are typically found in homes and at places of business such as schools or offices. Usually a LAN will provide high data transfer speeds to the nodes connected due to their small geographical size compared to other types of networks.
The most common technologies in use to connect a LAN are Ethernet and Wi-Fi. If you have a router in your home (connected to a modem or directly to the Internet) and you use multiple computers connected to it (wired or Wi-Fi) simultaneously, that technically qualifies as a local area network. Your modem provides you with a connection to a larger MAN, WAN and Internet (depending on your provider's system.)
The need for LANs was realized as far back as the 1960s when research labs gathered increasing numbers of computers. As time went on, the need for a network to facilitate the sharing of resources (such as printers) over a network became apparent. All types of proprietary solutions from vendors came about and while they worked in practice, they only worked under the right conditions. They would specify their own network cards, wiring systems and so forth and so the need for a more standardized solution was obvious.
Nowadays, the TCP/IP protocol has replaced the likes of IPX and NBF while Ethernet also became something of a standard for physically connecting up networks of computers. Later on, Wi-Fi became a common system in homes and is quickly becoming the most common technology for connecting up nodes into Local Area Networks.