Any of various aquatic or terrestrial reptiles of the order Testudines(or Chelonia), having horny toothless jaws and a bony or leathery shell into which the head, limbs, and tail can be withdrawn in most species.

• 龟龟鳖目的各种水生或陆生的爬行动物，有角质无齿的颌，骨质的或似皮革的壳，许多品种的龟可将头、四肢和尾缩进壳中