9 named features carry the IAU descriptor Chaos — terrain broken into a jumble of blocks and hollows on Europa, out of 39 in the mapped Solar System.
The IAU assigns each feature class on each world a naming theme. Across the 9 chaos with a recorded origin, one category covers them all, led by Celtic.
Every one has its own page, on the surface it sits on.
The same descriptor is used on 1 other world, for 30 more features.