Robert P. Munafo, 2008 Feb 21.
A colloquial name for mu-atom. This is confused substantially by the fact that ball is also used in formal mathematics to refer to the set of points inside a circle, sphere, etc.
From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2017. Mu-ency index
This page was written in the "embarrassingly readable" markup language RHTF, and was last updated on 2017 Feb 02. s.11