What Do Terms Like AU, AR, BI, and AE Mean on Ancient Coin Listings? 

Abbreviations like AU, AR, BI, and AE are common in ancient coin listings. Whether you are inspecting a slab, a catalog, or an auction listing, these terms specify a coin’s composition and understanding these abbreviations is critical for collectors, researchers, and numismatists.  

Why Use Abbreviations Instead of Full Metal Names? 

AU, AR, BI, and AE provide a consistent language across numismatics. Rooted in Latin, the administrative language of many ancient issuing authorities, these abbreviations reflect linguistic origins and preserve a classical context. 

Coin listings often include dense data such as issuing mint, weight, ruler, type, etc. Abbreviations minimize clutter and support quick comprehension, especially in auctions or online platforms. NGC Ancients, PCGS, and other grading authorities use these abbreviations on certified slabs, reinforcing standardization across the industry. 

Understanding Ancient Coin Composition Abbreviations  

AU – Aurum (Gold)  

Gold coins were minted for elite payments, diplomatic gifts, ceremonial dedications, and state reserves. This abbreviation is also commonly spelled AV. 

• Example: Roman Aureus 
  • Description: High-purity gold coin from the Roman Republic through Empire, often bearing imperial portraits. 
  • Significance: Used for propaganda and high-value state functions. 
• Example: Byzantine Solidus 
  • Description: High-purity gold coin that replaced the Aureus, also bore imperial portraits. 
  • Significance: Used for trade, military payments, and supporting the expansion of the Byzantine Empire. 

AR – Argentum (Silver) 

Silver coins formed the core of many ancient monetary systems, used in commerce, payrolls, and tribute. 

• Example: Athenian Tetradrachm 
  • Description: Iconic coin with the owl of Athena; widely circulated. 
  • Significance: The Tetradrachm was a symbol of Athenian power and commerce. 
• Example: Roman Denarius 
  • Description: Rome’s staple silver coin for over 400 years. 
  • Significance: Used in market transactions, taxation, and military pay. 

Note: Some archaic silver coins were made from electrum (EL), a naturally occurring gold-silver alloy used before refining techniques advanced. 

BI – Billon (Debased Silver) 

Billon coins mix low amounts of silver with copper or base metals. They were typically struck during times of inflation or silver scarcity. 

• Example: Roman Antoninianus 
  • Description: Began at ~50% silver under Caracalla in 215 AD, fell to under 2% by century’s end. 
  • Significance: Mirrored Rome’s economic instability. 
• Example: Medieval Billon Coins 
  • Description: Circulated throughout Europe, with widely varying silver content. 
  • Significance: Enabled monetary continuity during silver shortages. 

AE – Aerum (Bronze or Copper-Based Alloys) 

Bronze and copper-based coins were mass-produced for local trade and everyday transactions. They are the most commonly found coin type in archaeological digs. 

• Example: Roman Sestertius 
  • Description: Large bronze coin with detailed imperial imagery. 
  • Significance: Promoted civic values and facilitated provincial commerce. 
• Example: Greek AE Coins 
  • Description: Minted by city-states with symbols of local deities. 
  • Significance: Represented civic identity and enabled market exchange. 

Modern Use of AU, AR, BI, and AE 

These terms are deeply embedded in modern numismatics: 

• Auction Listings: Standard in catalogs (e.g., “AR Denarius”). 

• Digital Platforms: Used in filters on VCoins, CoinArchives, and acsearch.info. 

• Grading Slabs: NGC and PCGS label coins with these abbreviations. 

Important: In modern grading, “AU” may also mean “About Uncirculated” (e.g., AU-58). Always consider context if you are unsure about AU coins. 

Collecting Ancient Coins 

Abbreviations help collectors identify metal types on graded slabs. Reputable services like NGC Ancients verify: 

• Composition (AU, AR, BI, AE) 

• Authenticity 

• Condition 

Quick Reference: Ancient Coin Metal Abbreviations 

Abbreviation	Latin Term	Metal	Example Coins	Primary Use
AU	Aurum	Gold	Aureus, Stater	Tribute, elite payment, diplomacy
AR	Argentum	Silver	Denarius, Tetradrachm	Trade, taxation, salaries
BI	Billon	Debased Silver	Antoninianus, Billon	Local commerce, inflation-era currency
AE	Aerum	Bronze/Copper	Sestertius, Greek AE	Daily use, local trade

Each metal composition reflects a different layer of societal function, from military might to daily trade. Today, these terms connect modern collectors to a 2,000-year-old language of value, shaped in gold, silver, bronze, and billon—still speaking through the coins that survive.