What does aureus mean?
The aureus was the premier gold coin of ancient Rome, introduced by Julius Caesar shortly before his assassination and struck by emperors for more than two centuries thereafter. Valued at twenty-five silver denarii, it served as the empire's standard high-value currency, carrying portraits and propaganda messages of successive rulers on its obverse. Because so many examples survive in hoards and collections, the aureus remains central to numismatic study and is highly prized by collectors today. Beyond its monetary history, the same Latin word — literally meaning 'golden' — survives as a descriptive epithet in scientific naming, most famously in Staphylococcus aureus, the bacterium whose golden-hued colonies earned it the name. The word therefore bridges two worlds: the tangible wealth of antiquity and the enduring Latin vocabulary of modern science.
A gold coin of ancient Rome, first issued by Julius Caesar c. 46 BC and valued at 25 silver denarii; struck until the early fourth century AD when it gave way to the solidus.
"A hoard of aurei unearthed in Britain included coins minted under five different emperors."
Plural is the Latin 'aurei'; the anglicized 'auruses' is not standard.
In taxonomic and scientific usage, the Latin adjective meaning 'golden', used unchanged as a species or subspecies epithet.
"Staphylococcus aureus owes its specific name to the golden pigment of its colonies."
The Latin plural 'aurei' is standard in historical and numismatic contexts; an anglicized '-uses' plural is not established.
"The museum acquired forty-three aurei recovered from a shipwreck off the Italian coast."
One Roman aureus was worth 25 silver denarii — enough to pay a legionary nearly three months' wages.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of aureus
Aureus comes directly from classical Latin, where it functioned both as an adjective meaning 'golden, made of gold' (from aurum, gold) and as the name of Rome's gold coin, officially the 'aureus nummus'. Cognates sharing the aurum root include the English derivatives auriferous ('gold-bearing'), auric ('of gold'), and aureate ('golden'). The coin's Latin plural, aurei, remains the accepted English plural in scholarly use.
How aureus is actually used
The word is chiefly encountered in historical, numismatic, and archaeological writing, where the plural is conventionally the Latin form 'aurei'. In scientific contexts the identical spelling functions as a Latin adjectival epithet rather than as the noun.
Easily confused with aureus
Aureate is an adjective meaning golden or ornamented in a gilded literary style, whereas the aureus is a physical Roman gold coin.
An aureola is a halo or circle of light surrounding a sacred figure, while an aureus is an ancient Roman coin.