What is "patent yellow"

Yellow \Yel"low\, n.

1. A bright golden color, reflecting more light than any other except white; the color of that part of the spectrum which is between the orange and green. ``A long motley coat guarded with yellow.''
   --Shak.

2. A yellow pigment.

   Cadmium yellow, Chrome yellow, Indigo yellow, King's yellow, etc. See under Cadmium, Chrome, etc.

   Naples yellow, a yellow amorphous pigment, used in oil, porcelain, and enamel painting, consisting of a basic lead metantimonate, obtained by fusing together tartar emetic lead nitrate, and common salt.

   Patent yellow (Old Chem.), a yellow pigment consisting essentially of a lead oxychloride; -- called also Turner's yellow.