LAN (Local Area Network) is like the networking inside of your building. In this course it represents the network in our coffee shop. If devices are talking with the office PC, the TV, the WiFi Clients that’s all part of the LAN.
The WAN (Wide Area Network) is if you have to leave your local environment. In our example like if one of our coffee shop guests tries to open Netflix with our WiFi, he has to leave our local environment so that would be a WAN connection.