IT'S ALL IN THE NAME
Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), our founders decided to give it the short form ISO. ISO is derived from the Greek 'isos', meaning equal. Whatever the country, whatever the language, we are always ISO.
It all depends on your native language or your knowledge of Greek
How do you say an isosceles triangle