a period of U.S. history in the 1870s noted for political corruption, financial speculation, and the opulent lives of wealthy industrialists and financiers
Word origin
from the novel The Gilded Age (1873) by Twain & C. D. Warner
Gilded Age in American English
noun
the period in the U.S. c1870–98, characterized by a greatly expanding economy and the emergence of plutocratic influences in government and society