Theaetetus

Meanings

1. A classical Greek mathematician credited with proving that there are precisely five regular convex polyhedra.
2. A later middle dialogue of Plato concerning epistemology.
3. A lunar impact crater 2.8 kilometres in depth and 25 kilometres in diameter, located southeast of the crater Cassini, near the eastern edge of Mare Imbrium.

Etymology

From Ancient Greek Θεαίτητος (Theaítētos); the mathematician is the eponym of the dialogue and the lunar crater.