Podcast
A podcast is an audio recording stored on the internet, most often in MP3 format. It can be listened to directly through websites (streaming) or as a downloaded file through various applications.
Podcasts are often regular shows containing several episodes. Their point is that you can listen to anything at any time, even without a constant internet connection. Most are available free of charge and take the form of the spoken word on a range of topics.
History:
The name itself is derived from iPod, Apple's portable player, and broadcasting. The concept of distributing content this way first appeared in 2000 as audioblogging, but it was Ben Hammersley who began using this particular term in 2004. Apple attempted to trademark the name, but its application was definitively rejected in 2006. The technical principle behind podcasts was devised by Dave Winer and Adam Curry, who automated their downloading using RSS software.