Where the shape comes from
A pattern of fine, crossing stitches, the mark of decorative needlework rather than plain sewing. Genuinely rare today, it survives mainly as a dictionary classifier for a small handful of characters describing embroidered ceremonial patterns, its everyday work long since taken over by words built more simply from 糸, thread, and 衣, cloth.
汉字 filed under 黹
No published character on HSK Guide is filed under this radical yet. 汉字库.