A network is a collection of connected intelligent computing devices. The connection is not necessarily a fancy one. A connection between two computers by direct cabling is qualified to be a network. By this definition, a workstation which is loaded with a computer, a scanner, and a printer, is not treated as a network.
A network can consist of two computers connected together on a desk or it can consist of many Local Area Networks (LANs) connected together to form a Wide Area Network (WAN) across a continent. The key is that two or more computers are connected together by a medium and are sharing resources. These resources can be files, printers, hard?drives, or CPU number-crunching power.
A Local Area Network (LAN) is a smaller network within one location or between several buildings A Metropolitan Network (MAN, politically incorrect, no WOMAN!) is a midsize network spanning the city. A Wide Area Network (WAN) is a giant network spanning across several cities or even several continents.