A common rule of thumb for recessions is two quarters of negative GDP growth. On the other hand, whereas a depression is a prolonged period of economic recession marked by a significant decline in income and employment. Depressions are caused by the same factors that lead to a recession.
So in short recession means negative growth rate where as depression means prolonged recession for a significant time.
Example
Recession: 2001, 2008
Depression: 1930
