Internal IP address
Alternatively referred to as the local IP address, the internal IP address is the address that is assigned by your local network router that often begins with 192.168.x.x. These IP addresses can only be seen by other computers in your local network and not by any computers connected in an external network such as on the Internet.
To reach the Internet or a computer in another network your computer is often assigned an external IP address, which can then be used to refer to the computer in your local network.
In the above picture, there are three computers in the local network that have each been assigned their own internal IP address by the router. The ISP is connected to the router and gives the router an external IP address that allows it to communicate with the Internet. While on the Internet everyone sees your external IP address, but any information coming from the router is routed from the external IP address to the internal IP address.