crucial point; essential part; linchpin
Formal, somewhat literary term for the most important element or core of a matter. Often used in abstract or political contexts.
The crucial point of this reform proposal lies in the review of the education system.
important state affairs; key matters of governance
Refers specifically to critical matters of state or governance. Rare standalone use; more common in historical or political discourse.
外交政策の枢機を担う人物。
A person who holds the linchpin of foreign policy.
Those involved in important state affairs must always put national interest first.
cardinal (Catholic Church)
Compound of 枢 (pivot, hinge) and 機 (mechanism, opportunity), suggesting the central mechanism or pivotal point of a matter. The exact historical derivation is uncertain, but the kanji combination conveys the idea of a crucial, central element.