1. A French coin formerly used as currency, especially one issued before the adoption of the euro.
Usage: historical; often capitalized when referring to the European Currency Unit
2. A shield or the representation of a shield, especially in heraldry.
Usage: heraldry; archaic
3. The European Currency Unit, a former accounting unit used by the European Union before the euro.
Usage: finance; historical; often capitalized as ECU

Examples

• The museum displayed an old ecu from the reign of Louis XIV.
• Before the euro, the ecu served as a precursor to modern European currency.
• The heraldic ecu on the family crest featured a lion rampant.
• Collectors often seek rare French ecus from the 18th century.
• The ECU was replaced by the euro in 1999 for electronic transactions.