RSS are special file formats that have been continuously introduced since the beginning of 2000, and show changes on web pages.
These are mostly excerpted, with only some of the changes being displayed (a preview of a new post on a webpage, so to speak) and partly also a full text RSS feed.
- RSS today stands for: Really Simple Syndication (very simple summary).
- Feed stands for: feed, feed (in the sense of feed).
For those who want to get even closer to the terminology and background technology, can do this here: