The term "Gilded Age" refers to a period in late 19th-century American society characterized by rapid industrialization, economic growth, and widespread social issues. The term, coined by Mark Twain, implies a superficial glittering façade over underlying social problems such as poverty, racial tensions, and labor exploitation. During this era, the United States experienced significant technological advancements and an influx of immigrants, leading to urbanization and the rise of corporate monopolies. However, wealth was concentrated in the hands of a few industrialists while many workers faced harsh conditions. The Gilded Age laid the groundwork for the Progressive Era reforms of the early 20th century.