'Broadband' is the term used for any communication system that is able to transmit large volumes of electronic data. It's specific capacity definition has increased with time. Currently any connection that can support 'streaming' of multimedia, such as movies and music, which is played back while it is 'downloaded' may be considered 'broadband'. In general this means a connection of at least 256kbps or more. That is 4 or 5 times quicker than a regular 56kbps modem 'narrowband' connection.

If you consider the data travelling in cables around the Internet to be like water in pipes, a normal modem connection to the Internet is like a kitchen tap. It takes perhaps a minute or so to get a gallon from the tap, but you need it a lot quicker than that to fill a swimming pool. To get more water, in less time, a larger pipe and tap is needed.

In Internet terms this larger pipe is known as Broadband.