Metropolitan Area Network
A Metropolitan Area Network (MAN) is a computer network that spans across a wide populated area such as a campus, town or city, generally interconnecting Local Area Networks. A MAN can provide uplink services to the Internet (or to a separate WAN).
Physically a typical MAN would spread out to be the size of a several city blocks, or indeed an entire city. It could be considered the step between local area networks and wide area networks. Due to its size, a MAN would provide data speeds that were moderate to high, but certainly not - at least in most cases - achieve the types of speeds possible with a local area network.
A good example of a MAN is a CATV system that provides Internet and television services (and possibly VoIP). The network could be size of an entire town, connecting homes and business via cable. Those homes and businesses would contain small to large (relative) local area networks (wired or wireless) that are connected by equipment to the WAN, which in turn provides an uplink to the Internet.
In cities, MAN links between LANs can be achieved also using microwave or radio wireless communication, or if possible by use of infra-red laser which can carry data wirelessly over a distance in a straight line usually elevated from the ground.