What does crith mean?
The crith is a historical unit of mass used in physics and chemistry to weigh gases. It was defined as the mass of one litre of hydrogen gas measured at standard temperature and pressure, which works out at roughly 0.09 grams — making it one of the smallest named units of weight ever used in science. Because hydrogen is the lightest known element, the crith provided a convenient baseline against which the densities and molecular weights of other gases could be compared in older textbooks. The name derives from the Greek word for barley grain, reflecting an ancient tradition of using seeds as standards of weight. The crith fell out of use as chemists adopted the mole and SI units, and today it appears mainly in historical and archival contexts rather than in current measurement practice.
nounA crith is a former unit of mass used in physics, defined as the mass of one litre of hydrogen gas at standard temperature and pressure, equal to approximately 0.09 grams.
- A former unit of mass equal to the weight of one litre of hydrogen gas at standard temperature and pressure, approximately 0.09 grams.
"The density of the gas was expressed in criths for direct comparison with hydrogen."
"Early chemists quoted the molar volume of gases by reference to the crith as their standard of comparison."
"The table gave densities in grams per litre alongside the older measure of criths."
Regular plural, formed by adding -s; used when comparing multiple measurements of gas mass.
"Oxygen has a mass of nearly sixteen criths per litre under standard conditions."
A crith was literally the weight of a barleycorn's worth of history — its name comes from the Greek word for barley, yet it measured hydrogen, the lightest element in the universe.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of crith
The word "crith" comes from the Greek "krithē", meaning barley or a barleycorn, which served as one of the smallest traditional standards of weight in the ancient Greek world. The term was adopted into scientific English in the 19th century, when metrologists sought a natural, reproducible unit for expressing the mass of gases and settled on the weight of a litre of hydrogen at standard conditions. Its Greek root links it conceptually to other seed-based measures of antiquity, though few common English words share the lineage directly.
How crith is actually used
The crith is obsolete and survives only in historical scientific literature; modern usage expresses gas masses in grams or moles. It was chiefly encountered in late 19th- and early 20th-century chemistry texts.
Easily confused with crith
"Writhe" is a verb meaning to twist and squirm, especially in pain, whereas "crith" is a noun denoting a small unit of gas mass.
"Myth" refers to a traditional story or widely held false belief, while "crith" is an obsolete scientific unit of weight based on hydrogen.