What is a Podcast?

A podcast is a digital media file, or a series of such files, that is distributed over the Internet using syndication feeds for playback on portable media players and personal computers. The term "podcast," like "radio," can mean either the content itself or the method by which it is syndicated; the latter is also termed podcasting. The host or author of a podcast is often called a podcaster. The term "podcast" is a portmanteau of the words "pod" and "broadcast". The significance of "pod" refers to the Apple iPod, for which the first podcasting scripts were developed [1] (See History of podcasting). A popular alternate folk etymology attributes the meaning of "pod" to the backronym "portable on-demand", citing the previous usage of the unrelated storage container company Portable On Demand Storage.

source: -http://en.wikipedia.org/wiki/Podcast