"The Progressive Era is a term historians give to a roughly twenty-year period beginning with the watershed election of 1896 and ending with America's entry into World War I in 1917. The Progressive Era is notable for its spirit of political reform, its reassessment of laissez-faire (or unregulated) capitalism, and its scientific approach to social problems."
Source: Encyclopedia of Third Parties in America
"The novelist F. Scott Fitzgerald coined the term 'Jazz Age' retrospectively to refer to the decade after World War I and before the stock market crash in 1929, during which Americans embarked upon what he called 'the gaudiest spree in history."
Source: Dictionary of American History, 3rd ed.