n, pl  turtles  also  turtle  often attrib  :  any of an order (Testudines) of terrestrial, freshwater, and marine reptiles that have a toothless horny beak and a shell of bony dermal plates usu. covered with horny shields enclosing the trunk and into which the head, limbs, and tail usu. may be withdrawn - called also chelonian  .
 
 
 
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