Bermard Williams (194 n. 9) notes that Aristotle uses two words for shame, aischúnē and aidōs, pretty much interchangeably.
In his Nicomachean Ethics, Aristotle defines aischúnē as fear of disgrace or disrepute. (NE IV.9 1128b11) In his Rhetoric, Aristotle defines aischúnē as “pain or disturbance in regard to bad things, whether past, present, or future, which seem likely to involve us in discredit ….” (R. ii.6 1383b15-17)
Before Aristotle, Plato has Socrates using aidōs to ask Euthyphro: “For is there anyone who, in feeling shame and embarrassment at anything, does not also at the same time fear and dread … ?” (Euthphr. 12c) Elsewhere in his Nicomachean Ethics (1108a32), Aristotle uses aidōs to refer to sobriety and moderation. More generally, aidōs concerns respect for others, their feelings and their limitations, even forgiveness for their faults. In his translation of Euripedes’ Alcestis, Beye notes that the English word “shame” is not exactly equivalent to the Greek aidōs, which “is almost untranslatable outside a paragraph of explanation. Humility, awe, a sense of shame, reverence—all are combined in the word.” (Beye 92)