Criticality
Etymology
From Greek kritikos, "able to discern or decide," from krinein, "to separate, judge" — the same root as "crisis," the decisive turning point. Physics uses "critical" for the exact conditions of a phase change, and "criticality" names that poised state, notably in nuclear chains and in the theory of self-organized criticality.
noun · /krit-ih-KAL-ih-tee/
The knife-edge state at which a system is perfectly poised to tip, so that a single small disturbance can spread through the whole of it.
What it names
The condition just before a big shift — a market, a crowd, or a forest — where everything looks stable but any spark could now propagate everywhere.
Example
By the final week the negotiation had reached criticality, where a single careless word from either side could have collapsed the whole deal.
Related idea
Criticality is the poised state at the tipping point itself; a threshold is the specific level whose crossing pushes a system into that state.