Note that the terminology, as well as its history, is controversial, and hard to establish.
Tool vendors, as well as academics, may find an interest in introducing variants for differentiation purposes, sometimes trying so to reacquire pre-established acronyms.
Examples of related concepts impacting on the acronyms are Revision Control, Version Control, Source Control, Source Code, Change Management, Configuration Item, Software Configuration, Change Set, Baseline.
In particular, the former vendor, Atria, later Rational Software, now a part of IBM, is known to have used SCM as Software Configuration Management.