Eunoia is the shortest English word containing all five main vowel graphemes.
(rhetoric) Goodwill towards an audience, either perceived or real; the perception that the speaker has the audience's interest at heart.
(medicine, psychology) A state of normal adult mental health.
Origin
From Ancient Greek εὔνοια (eunoia, “goodwill”, literally “beautiful thinking”), from εὖ (eu, “well, good”) + νόος (noos, “mind, spirit”).