linchpin
n. 1 pin passed through an axle-end to keep a wheel in position. 2 person or thing vital to an organization etc. [old english lynis = axle-tree]
n. A pin used to prevent the wheel of a vehicle from sliding off the axletree.
n. 1 pin passed through an axle-end to keep a wheel in position. 2 person or thing vital to an organization etc. [old english lynis = axle-tree]
n. A pin used to prevent the wheel of a vehicle from sliding off the axletree.