Definition of "red lead" []

• A poisonous bright red powder, Pb3O4, used in paints, glass, pottery, and packing for pipe joints. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The object of the use of red lead and other red coloring matters is two fold: first, to conceal other adulterations, and second, to preserve the color of the cayenne, as when exposed to the light for any time it usually loses part of the bright red color which it at first possesses, and therefore it becomes deteriorated in the eyes of the purchaser."