The farmer harvested the barleycorn to make beer.
A unit of length equal to one-third of an inch, based on the length of a grain of barley. The shoe size was measured using the barleycorn as a unit.
(archaic) A unit of weight equal to approximately one-third of a grain, historically based on the weight of a single grain of barley. The goldsmith calculated the ring's mass in barleycorns.