Noun
(literally) A currency that is common to several countries.
A standard of measurement that can be used for comparing disparate things.
(figuratively) Common practice; a widespread idea, a commonplace habit.
Source: en.wiktionary.orgA common currency imposes on us a duty to cooperate more on policy. Gerhard Schröder
Nations with a common currency never went to war against each other. A common currency is more than the money you pay with. Helmut Kohl
A national currency, with the Euro as a common currency - that wouldn't bother me. Marine Le Pen