Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French), our founders decided to give it the short form ISO. ISO is derived from the Greek word isos (ίσος, meaning "equal"). Whatever the country, whatever the language, the short form of our name is always ISO.
I was gonna reply the "S" in "ISO" stands for "standardization" but apparently ISO doesn't stand for anything.
I was expecting a KFC situation, but no: