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 (February 11, 1847 â October 18, 1931) was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb.dison developed a system of electric-power generation and distribution to homes, businesses, and factories â a crucial development in the modern industrialized world. His first power station was on Pearl Street in Manhattan, New York.