linchpin
UK[ˈlɪntʃpɪn]US[ˈlɪntʃpɪn]
n
a person or thing that is the most important part of a group or system, because everything depends on them or it
n
a pin passed through the end of an axle to keep a wheel in position
Morpheme Breakdown
linch
pin
linch
catch, seize
pin
fastening peg
Etymology
the word 'linchpin' is a compound formed from two old english elements. the first part, 'linch', evolved from the old english lynis, which conveyed the sense of catching or holding something secure. the second part, 'pin', derives from the old english pinn, a common term for a peg or bolt used for fastening. originally, a linchpin was the literal pin inserted through the axle of a wheel to prevent it from sliding off. over time, this critical, securing function provided a powerful metaphor, leading to its modern abstract meaning as the indispensable central element upon which a system or organization depends.
Analysis
Structure: linch (catch, seize) + pin (fastening peg)
linch originates from old english lynis, meaning "catch, seize, or hold". pin originates from old english pinn, meaning "peg, bolt, or fastening device".
Examples
trust is the linchpin of any successful relationship.
the new evidence became the linchpin of the prosecutor's case.
in older carts, a linchpin was essential for keeping the wheels attached.