Was a stamp ever called a euro?

Yes, there was a stamp called a "Euro" issued in several European countries. For instance, the European Union issued a commemorative stamp featuring the euro currency symbol in 2002 to mark the introduction of the euro banknotes and coins. Additionally, various postal services in Eurozone countries may have released stamps that reference the euro in their designs. However, the term "euro" primarily refers to the currency itself rather than stamps.