"Brian Eno suggested the word to convey the extreme creativity that groups, places or "scenes" can occasionally generate. [...] "Scenius stands for the intelligence and the intuition of a whole cultural scene. It is the communal form of the concept of the genius." https://www.wired.com/2008/06/scenius-or-comm/
Eno explains scenius brilliantly in this 3-min clip. https://www.youtube.com/watch?v=qkD7JBspgas