χέλυς
χέλυς
.χέλυς, ῠος, ἡ,
a tortoise, Lat. testudo:—then, since Hermes made the lyre by stretching strings on its shell, which acted as a sounding-board, χέλυς came to mean the lyre, Hhymn. (to Merc.), Eur.
the arched breast, the chest, from its likeness of shape to the back of a tortoise, Eur.