EMZETT.MAN
In short: Metropolitan Area Network — a network that connects several LANs within a city or region.
In more detail: A MAN spans roughly 5 to 50 kilometres. Typical operators are city utilities, telecom companies, universities and authorities. They use it to link sites such as the town hall, schools and libraries over their own or leased fibre lines.
In Depth
MANs are often built as fibre rings (see ring topology): if one line fails, traffic continues in the opposite direction. A MAN is faster and cheaper than a WAN over long distances, but larger and more expensive to run than a LAN. Examples are a city fibre network or the shared network of several university sites in one city.