linchpin

noun

1. A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device.

   “In ij camellis ferri vocatis lynspins emptis pro carectis iiijᵈ.”

   “Every design that villany could suggest was had recourse to in the hopes of nobbling Wild Dayrell; but never being left for an hour by either his trainer or jockey, he escaped the intended “coopering,” even when the lynchpins of the wheels of his van had been tampered with.”

   “The axles were attached to the wooden floors with leather straps, the floor projecting on each side to take the wheels which were secured by linchpins to their outer faces.”

2. (figuratively)A central cohesive source of stability and security; a person or thing that is critical to a system or organisation.

   “What is difficult to appreciate, however, is the discrepancy between his statement to the 'Manchester Guardian' correspondent and his known abhorance for party politics, which is the lynchpin of modern democracy.”

   “Community nurses have been described as the lynchpins of palliative care in the community.”

   “Second, QAnon, whose adherents have deep ties to countless other large communities, has become a linchpin in that ecosystem, and the absurdity of its claims in no way reduces its political influence.”

verb

1. (ambitransitive)To adopt as, or serve as, a central cohesive source of stability and security.

   “The poems turn fear of individual death into an audit of the costs of an aristocratic status quo which is linchpinned by a monarchy indulging in paradigms of social redress that have become cosmetic, opportunities for self-display rather than genuine justice.”