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.
Thomas Alva Edison was born on February 11, 1847 in Milan, Ohio, U.S. At age 84, he died on October 18, 1931 in West Orange, New Jersey, U.S. From 1886 until the time of his death, he was married to Mina Miller. He had six children named Marion, Thomas, William, Madeleine, Charles, and Theodore.