LANs are also used to transmit e-mail between personal computers in an office, or to attach all the personal computers in the office to a WAN or to the Internet. It is used more specifically to refer to the data communications wiring and equipment that ties the personal computers to the file server and the printer. For example, someone once asked me if an Ethernet could do the same thing as a LAN, like provide you with disk space. This website deals with this latter, more specific, sense of the term. Ethernet An example of what is called a LAN technology, or in the more specific sense of the word LAN, one of several types of LANs.
Ethernet is the most common type in use today.
This website has a number of pages for further information including a page of links to various LAN tutorials around the net. You may find browsing LAN Glossary to be of some use, though it is certain to raise as many questions as provide answers.