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
Parsec
A parsec (pc) is a unit of distance used in astronomy, equal to about 3.26 light-years or roughly 31 trillion kilometers. The name “parsec” comes from “parallax of one arcsecond,” referring to the method astronomers use to measure distances to nearby stars based on their apparent shift when viewed from different positions in Earth’s orbit. Parsecs are commonly used to measure distances to stars and galaxies. For example, the nearest star system, Alpha Centauri, is about 1.3 parsecs away. The symbol for parsec is "pc". It’s a convenient unit for expressing large astronomical distances beyond the reach of light-years.
No conversions available for length.