What is "potone"

Potone ( Pōtónē or Ποτώνη Potónē; born before 427 BC) daughter of Ariston and Perictione, was Plato's older sister. Her mother was Perictione and she was born in Collytus, just outside Athens. She married Eurymedon of Myrrhinus, by whom she bore Speusippus.

Roger Scruton's mock Platonic dialogue, Perictione in Colophon, introduces a daughter of Potone, Perictione.