Where the shape comes from
A narrow-necked jar for wine, the flare of the opening and the rounded body both visible in its strokes — the vessel that gave its shape to the whole family of characters about fermented drink. Water added beside it gives 酒, wine, alcohol, the liquid drawn out of the jar itself; and it sits at the root of 酸, sour, and 醉, drunk, the taste and the effect both traced back to the same jar.
汉字 filed under 酉
No published character on HSK Guide is filed under this radical yet. 汉字库.