D defs.my
Entry 1 sense Webster, 1913

Linchpin

/(lĭnch"pĭn`)/ · Linch·pin · IPA /ˈlɪnt͡ʃˌpɪn/
01 n. A pin used to prevent the wheel of a vehicle from sliding off the axletree.
  1. 1.
    A pin used to prevent the wheel of a vehicle from sliding off the axletree.