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Chelonia),having horny toothless jaws and a bony or leathery shell into which the head,limbs,and tail can be withdrawn in most species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