A person who loves progressive
music, whether it'd be Progressive
Rock or Progressive
Metal, Experimental or Neo-Prog, he loves the genre. Usually prog bands like ELP, King Crimson, Genesis, Dream Theater, Porcupine Tree, Pink Floyd, Frost*, Haken etc...
My brother Matt, he's such a Prog Frog. His record collection
consists of Frank Zappa, Dream Theater, Rush, King Crimson, Yes and bands of that nature.