Barleycorn
A barleycorn is an old English unit of length, traditionally based on the length of a grain of barley. It is defined as exactly 1/3 of an inch or approximately 8.47 millimeters.
Historically, the barleycorn was used for measuring small lengths and was also the basis for the inch, which was originally considered to be three barleycorns long. It played a role in various traditional measurements, including shoe sizing in English-speaking countries, where shoe sizes were sometimes expressed in barleycorn units.
Although obsolete as a formal unit, the barleycorn remains culturally significant, especially in shoe sizing systems.
Summary:
1 barleycorn = 1/3 inch ≈ 8.47 mm
Based on the length of a grain of barley
Used historically in small measurements and shoe sizing
Mostly of historical and cultural interest today
Exameter
An exameter (Em) is a very large unit of length in the metric system. It equals one quintillion meters (1 exameter = 10¹⁸ meters). Exameters are used mainly in astronomy and physics to describe enormous distances, such as those between galaxies or across the universe. Because this unit is so huge, it’s not used for everyday measurements. The exameter helps scientists talk about the vast scale of space in a simpler way.
No conversions available for length.