So you ask a Professor of Epistemology for the definition of the word ‘Knowledge’.
He might give you list [a safe response] but odds are that on that list is the phrase ‘Justified True Belief’ or something very close. [The original translated phrase from the Classical Greek is ‘True Belief with an Account’].
What’s so special about ‘Justified True Belief? It is the closest thing we have to an original definition for the word ‘Knowledge’. And it first emerges in the Theaetetus, in Plato’s Dialogues. Hence it is the ‘Classic’ definition.
The Theaetetus is where it all began. It is the source, the Mother-Lode for this subject called Epistemology.
But the Theaetetus, this founding source for the classic definition of ‘Knowledge’ is not about what ‘Knowledge’ is, but rather about what it is not. And why the word ‘Knowledge’ cannot be defined [read it].