The hallmark definition associated with 'the Age of Enlightenment' refers to a cultural and intellectual movement in the 17th and 18th centuries characterized by an emphasis on reason, individualism, and skepticism of tradition. Thinkers, or "philosophes," promoted ideals of liberty, democracy, and scientific inquiry, challenging established norms and advocating for social reform. The Enlightenment laid the groundwork for modern democratic governments and influenced significant developments like the American and French Revolutions, ultimately shaping contemporary Western thought and values.