The business cycle
The business cycle is an important feature of market economies: gross domestic product (GDP) alternately grows and contracts. A long period of expansion is called a boom. But after an upturn at some point there will inevitably be a downturn.A downturn that lasts more than six months is called a recession; one that lasts for a year is called depression or slump. There seems to be a permanent business cycle of boom and recession, upturns and downturns.