I think of it as ‘the joining’.
Joining. Joining with.
A therapy term.
My understanding of it:
You attempt to deeply understand your client.
You sit alongside them, metaphorically and maybe even physically – as opposed to opposing them!
You tune in, empathise, level out the hierarchy.
You ‘reverse roles’ in psychodrama-speak.
You bring your humanness to BE WITH them in their humanness.