Interesting question. One of my work colleagues asked me this on Friday last and I tried to explain in terms of classical mixed with rock, long complex tunes with many layers and usually pretty talented and well-trained artists. Gatefold sleeves, Roger Dean, dragons and magic, two tracks per album… that kind of thing. I assume there is a dictionary definition. Let’s see… *rummage rummage* ah! Prog Archives Definition of Prog Rock There you go. There will be a test later.