A lot of new words popping up these days thanks to cyber-technology.
The word "podcast" is a concatenation of the words iPod and broadcast. The underlying technology used for podcasts, called RSS (Really Simple Syndication) is capable of containing any type of media including audio, video, graphics, and more.
Here's a link to some Frequently Asked Questions about podcasting.
Incidentally, that (RSS) is exactly the same underlying technology blogs use. It is a fabulous content management system in these days of "information overload." (You gotta know someone as lazy as I wouldn't be manually surfing the 'Net for articles to post here...)
Almond Rocks is the RSS feed I use to scan headlines and blogs. It's a handy, dandy little aggregator and so incredibly easy to use. Highly recommended.