Abnormally thick skin.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Examples from the Web for pachyderma
Historical Examples of pachyderma
In the Hyla bistincta group, Hyla pachyderma is unique in having enlarged nuptial spines.
Hyla robertsorum, pachyderma, and crassa are the most aquatic members of the group.