Webster's Revised Unabridged Dictionary · 1913

Barleycorn

Barleycorn ({not transcribed}) , noun

[See Corn.]

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.
Collocations (1)
John Barleycorn , a humorous personification of barley as the source of malt liquor or whisky.