DEFINITION of 'Purchasing Power Parity-PPP'. An economic theory that estimates the amount of adjustment needed on the exchange rate between countries in order for the exchange to be equivalent to each currency's purchasing power.
Thomas Edison's most famous invention, the lightbulb, paved the way for modern life.
Charles Edison (August 3, 1890 - July 31, 1969), son of Thomas Edison, was a businessman, Assistant and then Acting Secretary of the Navy, and governor of New Jersey.