The dialogue about what Self-Sovereign Identity (SSI) really is, that was started in the blog "The Path to Self-Sovereign Identity" by Christopher Allen in 2016, has not resulted in a consensus today. While some see the ten principles of SSI that Allen proposed as the definition of SSI, he formulated them as "a departure point to provoke a discussion about what's truly important". And it is obvious that what is important differs per party.
The perspective that the eSSIF-Lab framework takes is that of supporting (autonomous) parties as they negotiate and execute electronic (business) transactions with one another. So anything that helps - e.g. concepts/ideas, architectures, processes and technologies, will be covered by that term.
The purpose of having the term Self-Sovereign Identity (SSI) is that it is an easy way to indicate what is within and what is outside the scope of the eSSIF-Lab framework. Anything in scope is covered by this term, and everything else is not.