Threshing, or thrashing, is the process of loosening the edible part of grain from the straw to which it is attached. It is the step in grain preparation after reaping. Threshing does not remove the bran from the grain.

A threshing board, also known as threshing sledge, is an obsolete agricultural implement used to separate cereals from their straw; that is, to thresh. It is a thick board, made with a variety of slats, with a shape between rectangular and trapezoidal, with the frontal part somewhat narrower and curved upward and whose bottom is covered with lithic flakes or razor-like metal blades.