What do the letters “ISO” stand for? Nothing!

It’s not an acronym. I didn’t know that.

I assumed it stood for “International Standards Organisation” but when I looked that up found there is no such thing. There is an “International Organisation for Standards”.
From their website:
“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.”
So why do they capitalise “ISO”? I haven’t a clue.
Interestingly, Willy Kuert  (the Swiss delegate to the 1946 London Conference which founded ISO) recalls:
“The first question that had to be settled in London was that of the name of the new organization. There were different proposals. The English and the Americans wanted “International Standards Coordinating Association”, but we fought against the word “coordinating ”. It was too limited. In the end ISO was chosen. I think it is good ; it is short. I recently read that the name ISO was chosen because “iso” is a Greek term meaning “equal”. There was no mention of that in London!”