- Enter a word for the dictionary definition.
From The Collaborative International Dictionary of English v.0.48:
Trionyx \Tri*on"yx\, n. [NL., fr. Gr. ? (see Tri-) + ? a claw.] (Zool.) A genus of fresh-water or river turtles which have the shell imperfectly developed and covered with a soft leathery skin. They are noted for their agility and rapacity. Called also soft tortoise, soft-shell tortoise, and mud turtle. [1913 Webster] Note: The common American species (Trionyx ferox syn. Aspidonectus ferox) becomes over a foot in length and is very voracious. Similar species are found in Asia and Africa. [1913 Webster]