RSS is a web contents distribution format, its name is the acronym for Really Simple Syndication.

It defines a data XML structure which is able to contain news, it is constantly updated by RSS service suppliers with new info.

Its standard format allows every RSS reader (AKA aggregator) to display together information belonging to different areas, so that the user is constantly updated without visiting too many websites.

If you want to know something more about RSS, look for it on Wikipedia.