tortoise

Etymology

From Middle English tortuse, tortuce, tortuge, from Medieval Latin tortuca, of uncertain origin. May be from Late Latin tartarūcha, from tartarūchus, from Ancient Greek ταρταροῦχος (tartaroûkhos, “holder of Tartaros, Tartarus, the land of the dead in ancient stories”), because it used to be thought that tortoises and turtles came from the underworld and they were commonly paired with such infernal beasts; or from Latin tortus (“twisted”). Displaced native Old English byrdling.

noun

1. Any of various land-dwelling reptiles, of the family Testudinidae (chiefly Canada, US) or the order Testudines (chiefly UK, Australia, New Zealand, Ireland, South Africa, India), whose body is enclosed in a shell (carapace plus plastron). The animal can withdraw its head and four legs partially into the shell, providing some protection from predators.
2. Synonym of cat (sense 10, a wheeled shelter)