In Ido, there is a rule that "every word pertaining to a national or local custom will get imported to the language without change or adaption, both the singular and the plural forms alike" (known as "vorti stranjera" – foreign words). This gets especially applied to "currencies, weights and measurements that don't belong to the metric system" (according to KGD, Kompleta Gramatiko Detaloza – Ido's grammar book). Thus the best word for "euro" would be just "euro", like "dollar" and "pound", with the plural probably kept the same: "euro", since most languages do that. In common speech, though, many Idists commonly refer to the currency as "euro" and "euri" as if it got fully adopted to the language because of the common use of the currency.