People often assume that ISO stands for "International Standards Organization". But in English the full name of the organization is "International Organization for Standardization". Oh, it must be the initials of the French name, some clever people suggest. But the French name is "Organisation internationale de normalisation".
ISO isn't an acronym or initialism at all: it's based on the prefix iso- derived from the Greek ἴσος "equal".
Another example of a non-initialism is UTC. In English, this atomic clock based version of GMT is "coordinated universal time". In French it's "temps universel coordonné". So why UTC? Well, it was just a compromise between CUT and TUC to keep both the English-speaking world and French-speaking world happy.