Bautz-Morgan classification

Bautz–Morgan classification

(b'owts mor -găn) A classification system for clusters of galaxies that is based on the degree to which the cluster is dominated by its brightest galaxies. Type I clusters have a single central cD galaxy, type II have a normal giant elliptical galaxy at the center, and type III have no dominant cluster galaxy.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Bautz-Morgan classification

[′bau̇ts ′mȯr·gən ‚klas·ə·fə‚kā·shən]
(astronomy)
A classification of clusters of galaxies into three categories, ranging from type I in which the cluster contains a supergiant elliptical galaxy, to type II in which the cluster contains no member that is significantly brighter than the general bright population.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.