L-A-N stands for "Local Area Network." A LAN is a computer network limited to a small area such as an office building, school campus, or even a residential home. Most mid to large-sized businesses today use LANs, which makes it easy for employees to share information. Currently, the most common type of LANs are Ethernet-based and use software from Novell or Oracle. However, with the emergence of wireless networking, wireless LANs have become a popular alternative.
W-A-N stands for "Wide Area Network." It is similar to a Local Area Network (LAN), but it's a lot bigger. WANs are not limited to a single location. Many wide area networks span long distances via telephone lines, fiber-optic cables, or satellite links. They can also be composed of smaller LANs that are interconnected. The Internet could be described as the biggest WAN in the world.