What does congius mean?
The congius was a standard unit of liquid capacity in ancient Rome, defined as six sextarii and amounting to approximately 3.3 litres — a little under a modern imperial gallon. It served as a practical measure for commodities central to daily Roman life, including wine, olive oil, and water, and appears in legal, commercial, and military contexts: soldiers' rations, for instance, were reckoned in congii. The word passed into scholarly and historical English usage, where it can also denote an equivalent older English liquid measure. Today it survives almost exclusively in historical writing, classical scholarship, and dictionaries of archaic measures, giving it a distinctly learned register. Its plural is congii, following the Latin form. Though obsolete as a working unit, the congius remains useful shorthand for writers and readers engaging with Roman commerce, law, and daily life, where quantities of liquid were routinely expressed in this measure.
nounA congius was an ancient Roman unit of liquid measure equal to six sextarii, roughly 3.3 litres (about three-quarters of a US gallon). The term is also used historically for an equivalent English liquid measure.
- An ancient Roman unit of liquid capacity equal to six sextarii, approximately 3.3 litres.
- A historical English liquid measure corresponding to the Roman congius.
"Each legionary received a daily ration of one congius of wine."
"The amphora held just over two congii of oil."
"Roman law specified tribute and rations in units such as the congius."
The plural follows the Latin second-declension pattern, so 'congius' becomes 'congii'; anglicized forms are not established.
"The recipe called for two congii of wine."
In ancient Rome, a soldier's daily ration of wine came to roughly one congius — about 3.3 litres poured out per man.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of congius
The word comes directly from Latin cōngius, the name of a Roman liquid measure. Its further origin within Latin is uncertain, though some have proposed a borrowing from Greek. English adopted the term in the early modern period, when classical learning brought many Roman metrological terms into scholarly use; the related Latin derivative congiarium denoted a largesse or gift measured out by the congius.
How congius is actually used
A learned, historical term encountered mainly in discussions of classical antiquity, ancient metrology, or older English texts; it does not occur in everyday modern speech. The standard plural is 'congii'.
Easily confused with congius
Contagium refers to the poison or infection by which disease is transmitted, whereas a congius is an ancient Roman liquid measure.