archaic or literary the inner or central part or point of something
in somebody's midst
among a group of people, or within a group or organization
It was clear that we had an informer in our midst
in the midst of
in the middle of (something); surrounded or beset by (something)
during or around the midpoint of (something)
I arrived in the midst of the celebrations
[Middle English middest, alteration of middes, back-formation from amiddes amid]