thresh, threshing

Definition

The terms "thresh" and "threshing" refer to the process of separating wheat grain from the rest of the wheat plant.

Plants to be threshed were first beaten (or trampled by oxen) to separate the straw from the grain and the chaff. Then the grain and chaff were tossed into the air, allowing the wind to blow the chaff away while the grain fell back down on the threshing floor.
A "threshing floor" is a large, solid, flat area that is used for threshing grain.
In biblical times, a threshing floor was a large flat rock or an area of packed-down dirt, giving a hard, level surface to crush the grain stalks and remove the grain.
A "threshing cart" or "threshing wheel" was used to crush the grain and help separate it from the chaff.
A "threshing sledge" or "threshing board" was used for separating grain. It was made of wooden boards that had sharp metal spikes on the end.