[soft.shell] n (1771): any of a family (Trionychidae) of aquatic turtles that have sharp claws and mandibles and a flat shell covered with soft leathery skin instead of with horny plates--called also soft-shelled turtle
SOFTSHELL
Meaning of SOFTSHELL in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012