A computer network is a physical or logical connection between any two computers. These networks are of three types
Local Area Network (LAN)LAN is a connection between two computers which are physically less than 1 km distant. This network usually exists in the office.
Metropolitan Area Network (MAN)MAN is a connection between the computers whose distance is less than 100 km in between. This was designed to connect different offices located in the same city. Because of the internet popularity, this is no longer in use.
Wide Area Network (WAN)WAN is a connection between any computers on the earth. There are no distance limits for this. The best example for WAN is Internet. An internet is a connection of connections.