Network of computers:-

A computer network is basically a network (a physical connection using wires, cables, optic fibres etc. It can be internet, intranet, a LAN connection, etc. (remember, these words can mean the same thing in most aspects and can mean two or more different things like here they mean different). See, when a computer is connected to internet, it is can be connected to all of these networks, for example, a computer can be connected to LAN when other computers are also connected to the same network (same connection), and they all are connected to a WAN since they are connected to internet. Sounds boring? No.

Intranet is a network which is mainly utilised by a single organisation, business, government, etc. and it can be accessed over internet (if made available over internet). Intranet can act as LAN when this network is only available in a same building or, a same place (if it is not accessible from any other part of the globe ,i.e., the network which is not accessible on internet). This same intranet can behave as WAN if this network is accessible on internet and suppose an employee can use it from any other part of the world. Whereas Internet is a computer network which can be accessed by common people, or organisations, businesses, government, etc.

Internet is not one's property.