centermost
At the middle
Centermost means situated at the very center, the most central position possible.
It's the superlative form of central, emphasizing the exact middle point: the centermost ring of the target, the centermost seat in the row.
The word appears less frequently than central or middle, typically when precision about position matters.
middle
Central point or position
heart · nucleus · midmost · median · equidistant · bullseye · focal · pivot · axis · midway
pivotal
Vitally important, deciding
fundamental · critical · primary · principal · chief · main · focal · paramount · cardinal · preeminent
center, central, centrally, centrality, centric, centrist, centrism, centralize, centralization