The Collaborative International Dictionary of English v.0.48:
Hyosternum \Hy`o*ster"num\, n. [Hyo- + sternum.] (Anat.) See Hyoplastron. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Hyopastron \Hy`o*pas"tron\, n. [Hyo- + plastron.] (Zool.) The second lateral plate in the plastron of turtles; -- called also hyosternum. [1913 Webster]