In economics, a trough is a low turning point or a local minimum of a business cycle. The time evolution of many economics variables exhibits a wave-like behavior with local maxima (peaks) followed by local minima (troughs). A business cycle may be defined as the period between two consecutive peaks.[1][2]
The period of the business cycle in which real GDP is increasing is called the expansion, in which the real GDP moves from the trough towards the peak.[3]