Question

What were the authors saying about the period in united states history between 1870 and 1900 by calling it the ""gilded age?""

Answer 1

Gilded means covered with a thin leaf of gold, or tinted to a gold color. Basically the object is made to look more appealing, expensive, showy, while concealing the inside, which is cheap.
By saying that 1879-1900 was the “Gilded Age”, they meant that the time looked splendorous and glittering on the surface, but was actually full of corruption.