A small terrestrial isopod crustacean of the genus Armadillidium closely related to the sow bug and having a convex, segmented, flexible body enabling it to curl into a ball when disturbed. In this sense also called roly-poly.
A sow bug.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.