linchpin /ˈlɪnt͡ʃˌpɪn/noun 2verb 1forms 3 noun2 •A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device. •(figurative) A central cohesive source of stability and security; a person or thing that is critical to a system or organisation.Community nurses have been described as the lynchpins of palliative care in the community. — 2013 verb1 •To adopt as, or serve as, a central cohesive source of stability and security. formslinchpinned · linchpinning · linchpins