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Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: Any of various small terrestrial isopod crustaceans of suborder Oniscidea, having a rigid segmented exoskeleton, usually feeding on dead plant matter and living in damp, dark places, such as under stones or bark. Several common species roll into a ball when disturbed, hence names such as pill bug and roly-poly. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.