The term "Gilded Age" refers to a period in U.S. history during the late 19th century, characterized by rapid economic growth, industrialization, and significant social change. Coined by Mark Twain, the phrase denotes both the glittering surface of wealth and the underlying problems, such as income inequality, political corruption, and labor exploitation. The Gilded Age highlighted the transformation of American society, fueling discussions about capitalism, class struggles, and the need for reform in response to the challenges of modern industrial life.