a former money of account of the European Common Market that was used in international finance until the euro was adopted and was based on the combined prorated values of the currencies of member nations.
Origin of ECU
E(uropean) C(urrency) U(nit), perhaps with play on écu
European Currency Unit: a former unit of currency based on the composite value of several different currencies in the European Union and functioning as both the reserve asset and the accounting unit of the European Monetary System; replaced by the euro in 1999
any of various former French gold or silver coins
a small shield
Word Origin for écu
C18: from Old French escu, from Latin scūtum shield
old French silver coin, 1704, from French écu, from Old French escu (12c.) "shield, coat of arms," also the name of a coin, from Latin scutum "shield" (see hide (n.1)). First issued by Louis IX (1226-1270); so called because the shield of France was imprinted on them.