Reconstruction Amendments: A collective term referring to three constitutional amendments passed between 1865 and 1870 - Thirteenth Amendment (abolishing slavery), Fourteenth Amendment (granting equal protection under law), and Fifteenth Amendment (prohibiting racial discrimination in voting rights).
Gilded Age: A period in American history from roughly 1870 to 1900 characterized by rapid industrialization, wealth accumulation for a few powerful individuals ("Robber Barons"), political corruption, and stark economic inequality.
Progressive Era: A period from around 1890 to 1920 marked by social activism aiming to address societal problems caused by rapid industrialization through reforms such as regulations on businesses, labor protections, women's suffrage movements, and efforts towards racial equality.