Below Full-Employment Equilibrium

What Does Below Full-Employment Equilibrium Mean?
A macroeconomic term used to describe a situation where an economy's short-run real gross domestic product (GDP) is currently lower than that same economy's long-run potential real GDP. Under this scenario, there is a recessionary gap between the two levels of GDP (measured by the difference between potential GDP and current GDP) that would have been produced had the economy been in long-run equilibrium.

Investopedia explains Below Full-Employment Equilibrium
When an economy is currently below its long-run real GDP level, there will be economic unemployment of resources, which will lead to an economic recession. The long-run real GDP level represents what an economy can produce had it been under full employment.

Full employment means the economy is utilizing all input resources (labor, capital, land, etc.) to its fullest potential. At full employment, there will still be natural unemployment in the labor market. This is unavoidable.