Socrates asks Euthyphro to offer him a definition of piety or holiness. The purpose of establishing a clear definition is to provide a basis for Euthyphro to teach Socrates the answer to the question: "What is piety?" Ostensibly, the purpose of the dialogue is to provide Socrates with a definitive meaning of "piety", with which he can defend against the charge of impiety in the pending trial.
Socrates seeks a definition of "piety" that is a universal (universally true), against which all actions can be measured to determine whether or not the actions are pious. To be universal, the definition of "piety" must express the 'essence' (ousia) of the thing defined (piety), a clear and unambiguous standard to which each particular instance of piety will conform.[5]
