Acronyms are abbreviations that are read as whole words rather than letter by letter — or in other words, they are words formed from initials of a phrase. "NATO" and "laser" are two examples.
I have seen abbreviations used in Latin, but I get the impression that they are often expanded to whole in speech or read as an abbreviation letter by letter. Not all abbreviations are suitable for acronyms. I will not try to pronounce "SPQR" as a single word…
Modern Latin has some acronyms, for example the name "NATO", but I wonder how new this phenomenon is. When did acronyms first appear in Latin? How do we know how they were read out? (Maybe they were declined?)
I have no guess as to what the answer might be, so any examples of acronyms with timing and explanation are welcome.