What is "woodlouse"

also wood-louse, 1610s, from wood (n.) + louse (n.). So called from being found in old wood.

n. Any of the terrestrial isopod crustaceans of suborder Oniscidea, which have a rigid, segmented exoskeleton, often being capable of rolling into a ball, and feed only on dead plant matter, usually living in damp, dark places, such as under stones or bark.

1. n. any of various small terrestrial isopods having a flat elliptical segmented body; found in damp habitats [syn: slater]

2. [also: woodlice (pl)]

A woodlouse (plural woodlice), also known by many common names (see below), is an isopod crustacean with a rigid, segmented, long exoskeleton and fourteen jointed limbs. Mostly they feed on dead plant material, and they are usually active at night. Woodlice form the suborder Oniscidea within the order Isopoda, with over 5,000 known species.

Woodlice in the genus Armadillidium and in the family Armadillidae can roll up into an almost perfect sphere as a defensive mechanism, hence some of the common names such as pill bug or roly-poly. Most woodlice, however, cannot do this.