Right phonetic
尧 — supplies the sound (yáo drifted to shāo, irregular but consistent across the family). Simplified from
堯, originally three
土 stacked over
兀 = a high mound, the legendary Emperor Yao's name. Pure sound-borrow here. Same phonetic in
浇 (water/pour),
绕 (wind around),
晓 (dawn),
翘 (raise) — all with similar onset drift.