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 Edison (1847 â 1931) was an American inventor and businessman who developed and made commercially available â many key inventions of modern life. His Edison Electric company was a pioneering company for delivering DC electricity directly into peopleâs homes.homas Edison was born in Milan, Ohio on Feb 11, 1847, the youngest of seven siblings. His parents were middle class, though they were not wealthy, especially when the railroad bypassed Milan, forcing the family to move to Port Huron, Michigan.