Coins.--

The classification of coins based on various characteristics. These characteristics may include:

• Denomination:  such as penny, nickel, dime, quarter, etc.
• Material:  such as copper, silver, gold, or a combination of these.
• Era: the time period in which they were minted, such as ancient, medieval, or modern.
• Design: design features, such as portraits, symbols, or abstract patterns.

These categories are used for numismatic purposes, specifically collecting and research.