Cage Match: Iso vs Exo

iso-

1. A prefix that means "equal,"

The American Heritage® Science Dictionary Copyright © 2005 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

Exo-
combining form

external, outside, or beyond

[from Greek exō outside]

Collins English Dictionary – Complete and Unabridged 6th Edition 2003. © William Collins Sons & Co. Ltd 1979, 1986 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003