Foremost, LAN stands for Local Area Network, WAN stands for Wide Area Network, while MAN simply means Metropolitan Area Network. These are three different types of networks that can be used to link multiple computer systems together. LAN is usually employed in connecting some numbers of computers that are within a limited geographical area.
For WAN, it can help to connects a group of computers within a higher range of geographical area, such as state, country or even continent. The coverage distance for MAN is more than that of LAN, but less than WAN. It is usually used in a town or city.
LAN has higher bandwidth for transferring network; WAN has lower bandwidth for transferring network; while the bandwidth for transferring network in MAN seems moderate. The distance limitation for LAN is between 100 to 1000 meters; that of WAN is about 100 thousand kilometers; while the distance coverage for MAN is up to 100 kilometers.