- any of various small terrestrial isopods, especially of the genera Armadillidium and Oniscus, which can roll themselves up into a spherical shape.
Origin of pill bug
An Americanism dating back to 1835–45
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- any of various woodlice of the genera Armadillidium and Oniscus, capable of rolling up into a ball when disturbed
Word Origin and History for pillbug
Online Etymology Dictionary, © 2010 Douglas Harper