LAN(Local area network)-A local area network (LAN)
 is a computer network that 

interconnects computers within a limited area 

such as a residence, school, laboratory, or 

office building

WAN(wide area network)-A wide area network (WAN) is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks often are established with leased telecommunication circuits.

Business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet may be considered a WAN