A woodlouse is a small grey creature, about the size of a fingernail, with a hard shell made of many little plates and lots of tiny legs. You find them under old wood, under stones, and in damp corners of the garden — anywhere dark and wet. When you lift the stone, they run away fast, and some kinds roll up into a small ball to protect themselves. The plural is 'woodlice' (not 'woodlouses'), the same way 'mouse' becomes 'mice'. People often call it an insect, and in everyday talk nobody will correct you, but scientists say it is not one: it is a crustacean, a relative of crabs and shrimps, which is why it needs damp air and dies quickly in a dry place. It has many local names — British children say 'pill bug', 'roly-poly', 'slater', 'cheesy bug' and a dozen more, depending on the town — but 'woodlouse' is the word you will see in books. It is not dirty and it does not bite; it eats dead leaves and rotting wood, so gardeners mostly leave it alone.

鼠婦（潮蟲、西瓜蟲）；會捲成球的那種俗稱「球鼠婦」。台灣一般人多半直接叫「潮蟲」或「西瓜蟲」，「鼠婦」比較像課本、生物課上的說法