The Question is Shown Below...Between 1865 and 1890, how was the term "Gilded Age" appropriate for describing this time period in US history?
Coined by Mark Twain, I'd say the phrase was perfectly appropriate for this time period. His point was that society itself had a gilded edge, a small group of incredibly wealthy individuals and a large number of very poor people who supported the wealth of the former.
The workers in sweatshops and meatpacking plants often worked long hours in horrible conditions for next to nothing - often $1 a day was the prevailing wage. The "robber barons" (called this by progressives of the time) profited off of the low pay and dangerous conditions, so much so that the top 1% of Americans controlled 60% of all the wealth. This disparity of wealth in the Gilded Age was the greatest it has ever been in our history, the difference so stark and shocking that Twain's assessment seems quite grimly accurate and appropriate.
The phrase "Gilded Age" implies that America at the time looked golden on the outside but was not really made of gold. You can argue that this was appropriate for the US of the time. The country in those days was golden with prosperity (most of the time) but had a less golden underside.
On the underside, there was, you can argue, too much poverty and abuse of the poorer people. There were sharecroppers in the South. There were many many factory workers in the North who were working for low pay in bad conditions. Meanwhile, the rich were spending extravagantly, making things look golden.