酸
さん · san · JLPT N1 · noun
acid
🍋 Radical 酉 means wine. Wine left too long turns sour, so 酸 (acid, sour) keeps the wine radical.
The 酉 radical means wine or alcohol. Vinegar and other acids form when wine ferments and goes sour, which is why 酸 carries that radical.
酸 — wine/jar radical 酉 + 夋 (phonetic)
酸 is a semantic-phonetic compound. The left side 酉 depicts a wine jar and signals meanings related to fermentation and alcohol. The right side 夋 supplies the sound. Originally describing the sour taste of fermented wine, it broadened to mean 'sour' in general and figuratively 'aching' or 'sad'.