Barleycorn

Bar·ley·corn

Barleycorn

n.
  1. A grain or “corn” of barley.
  2. Formerly , a measure of length, equal to the average length of a grain of barley; the third part of an inch.

Phrases & Compounds
John Barleycorn
a humorous personification of barley as the source of malt liquor or whisky.