linchpin noun
also lynchpin /ˈlɪntʃˌpɪn/ plural linchpins
also lynchpin /ˈlɪntʃˌpɪn/ plural linchpins
Learner's definition of LINCHPIN
[count]
: a person or thing that holds something together : the most important part of a complex situation or system关键人物;关键事物