red lead

[led] /lɛd/
noun
1.
an orange to red, heavy, earthy, water-insoluble, poisonous powder, Pb 3 O 4 , obtained by heating litharge in the presence of air: used chiefly as a paint pigment, in the manufacture of glass and glazes, and in storage batteries.
Also called minium.
Compare litharge.
Origin
1400-50; late Middle English
British Dictionary definitions for red lead

red lead

/lɛd/
noun
1.
a bright-red poisonous insoluble oxide of lead usually obtained as a powder by heating litharge in air. It is used as a pigment in paints. Formula: Pb3O4 Also called minium