Noun: linchpin 'linch,pin
- A central cohesive source of support and stability
"he is the linchpin of this firm";
- anchor, mainstay, keystone, backbone, lynchpin
- Pin inserted through an axletree to hold a wheel on
"The wagon's wheel came off when the linchpin broke";
- lynchpin
Derived forms: linchpins
Encyclopedia: Linchpin