IIRC, both SML and Standard ML were used to distinguish it within the ML family of languages before machine learning became popular.
Aren't they 2 separate languages? They have 2 separate Wiki articles:
https://en.wikipedia.org/wiki/Standard_ML
https://en.wikipedia.org/wiki/ML_(programming_language)
Or maybe the difference is more like Lisp vs Common Lisp.
"A Tour of Standard Meta-Language" is nonsense. If there's one really unfortunate thing about ML, it's that the expanded (original? source?) name of the language is so meaningless that nobody bothers to learn it. The name of the language really is ML, not something that ML happens to stand for. Though as others have said, the same is true of BASIC and COBOL.
"A Tour of SML" is still an abbreviation, is less clear for anyone who knows what Standard ML is, and is not the original title.
The first two hits that come up when I type ML into the algolia HN search (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...) are
"ML From Scratch, Part 1: Linear Regression" (301 points), which is about machine learning
and
"ML for the Working Programmer, 2nd Edition" (266 points), which is about ML
Which is the more ambiguous? Noting that the second one is about a thing whose name is ML, while the first is about a thing that is sometimes casually abbreviated to ML.
You have to call the language something. For decades it was mostly just referred to as ML. In recent years people (including me) have started calling it Standard ML explicitly to avoid confusing people who now expect ML to mean machine learning. It doesn't always work, as we see.
Expanding to "meta-language" sadly is no good either, since nobody has ever called it that and most practitioners wouldn't even recognise it.
SML is a possibility that's used often enough, but there's a semantic difficulty there - the difficulty is that Standard ML is the standard version of a language called ML; it isn't quite a language called SML.