noun
: any of numerous fiercely voracious aquatic turtles of the family Trionychidae having a flat, oval, or nearly round shell covered with soft leathery skin instead of with horny plates, a narrow head, nostrils at the end of a fleshy proboscis, and feet broadly webbed with but three claws and living in parts of Africa, Asia, and No. America, including the whole Mississippi valley, the Great lakes, and many southern rivers