Definitions 
A recession is a period of time where the economic output of a country or region declines.
Some economists and journalists often define a recession as two consecutive quarters in which the gross domestic product (GDP) decreases.
Recessions and the Economic Cycle
Most economies following what is known as an economic cycle. That is to say they experience a number of years of economic growth followed by a number of years of economic contraction.
Measuring Econmic Growth - How to spot a recession
