I have seen many people use SXD. I tend to use SD in my notes.
The X in SXD seems to be for “experience”, as in the acronym CX for customer experience, or UX, for user experience.
But personally, I try to avoid to use the use of such acronyms as much as possible. It makes it easier for people who are new to the field to know what we are talking about.
What do others use?
In this linkedin post I shared already 8 other service design practitioners shared what's the acronym they personally use.