Font names often contain cryptic abbreviations. It was even more murky in the “old days”, with severely strict limits on the length of fonts menu names. Although it’s gotten better over time, there are still plenty of font name abbreviations out there.
Abbreviations mostly fall in several common categories: foundry name, language, weight, and a few more. I’m embarrassed to admit that it was years before I knew the “SC” after a font’s name meant “SmallCaps.” Ugh!
In any case, Extensis has put together an exhaustive list of font abbreviations and their definitions, which you can check out here.