Quintile confusion

#1
Our business is requesting a new "Revenue Quintile" client dimension, but they are defining it in a strange way.

Basically they want to sort clients by revenue, then split them into 5 buckets (20% of total revenue each). So, client X will have a value of 1 if they are in top 20% and value of 5 if they are in bottom 20%. Bucket 1 will have a few clients, and bucket 5 will have the most clients, if that makes sense. Is there a better name for this than "quintile"? It doesn't seem to match the definition of quintile, since the population in this case is clients, but the variable is not an attribute of a client. I was thinking along the lines of "concentration ratio", but that doesn't quite fit either. I appreciate any help/pointers you can provide. Thank you.