sroylance, those terms have been defined:
I know what the acronyms stand for, but I do not believe that any of the terms have unambiguous universally accepted definitions. I, personally, like to refer to campus networks as 'extended LANs'.
Campus networks blur the lines:
We have a fiber run to the parking office which crosses over the street (city owned) on a connecting bridge (owned by us). It kinda leaves our property, but Its only a few hundred feet from my office, is it WAN?
We have data closets in a building around the corner from the parking garage. We own enough dark single-mode fiber from my building to that one that each closet gets its own GigE trunk back to the core in my building. We own the fiber, but probably not even the conduit it runs through.
Latency and throughput through the ATM core are similar to latency and throughput in the 'local' paths through the network, that certainly is not a characteristic of a classic WAN.
I have most often heard the term MAN to refer to networks like mine, too large (geographicly) to be consider strictly local, but not quite what could be considered wide area, I wouldn't say they are restricted to large companies and municipalities.
This entry was interesting, and led to some other interesting definitions as well.
All the *AN definitions are somewhat ambiguous.
If you asked 10 networkers what LAN means as opposed to WAN or MAN you would get 10 different answers.