Threshold (n.)   The means by which the edible germ of the wheat seed was separated from the hull (chaff). Derived from the term “thresh” or “threshing”.  This was achieved by striking the dried seeds with a stick called a flail.  The seed, separated from the chaff, was called the “thresh”.  The thresh (seeds), along with the chaff, were swept up and then pitched into the air allowing the wind to blow the lighter weight chaff out the door and the heavier seeds to fall to the floor.