A fall in demand that causes a lowering of economic activity,
less severe than a recession or slump.
A slowdown is limited growth over a short period of time.
A slowdown is characterized by slowed economic growth, but
growth nonetheless.
Recession:
A recession is a significant decline in economic activity
spread across the economy, lasting more than a few months, normally
visible in real GDP, real income, employment, industrial
production, and wholesale-retail sales.
A recession begins just after the economy reaches a peak of
activity and ends as the economy reaches its trough.
A recession is often defined as two fiscal quarters – six
months – of negative growth.