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.
List of Edison patents. Below is a list of Edison patents. Thomas Edison was an inventor who accumulated 2,332[1] patents worldwide for his inventions. 1,093 of Edison's patents were in the United States, but other patents were approved in countries around the globe.