Broadcasting is the distribution of audio and video signals - programmes - to a number of listeners or viewers that belong to a large public group. 

Broadcasting  -  information flow from the few to the many

Narrowcasting  -   information flow from the few to the few

Internet  -  information flow across traditional boundaries from the many to the many


Television and radio programmes are distributed through carrier wave and digital  broadcasting via satellite or cable.

Broadcasting via the Internet is webcasting.  In 2004 a new phenomenon occurred when a number of technologies combined to produce Podcasting,  which is an asynchronous broadcast/narrowcast medium.

The term "broadcast" was coined by early radio engineers,  and is chosen from the practice in farming, where the method of spreading seed using a wide toss of the hand is a broad  cast.

see   Broadcasting history