A fabric whose color couldn't be faked — nankeen's natural buff tint came from the cotton plant itself, not from any dye.
A yellowish cotton fabric originally made in Nanjing, China, or trousers made of this fabric.
From Nanking (now Nanjing), the Chinese city where this cotton cloth was originally manufactured and exported Key roots: 南京 (Nánjīng) (Chinese: "Southern Capital").
Nankeen's natural yellowish-buff color came from the cotton itself — it was made from a naturally pigmented variety of cotton grown near Nanjing, not from dyeing. When European manufacturers tried to imitate nankeen, they had to dye white cotton to match the color, since they couldn't source the same cotton variety.