linchpin

noun

linch·​pin ˈlinch-ˌpin 

variants or less commonly lynchpin

1

: a locking pin inserted crosswise (as through the end of an axle or shaft)

2

: one that serves to hold together parts or elements that exist or function as a unit

the linchpin in the defense's case

Did you know?

In his 1857 novel, Tom Brown's School Days, Thomas Hughes describes the "cowardly blackguard custom" of "taking the linch-pins out of the farmers' and bagmens' gigs at the fairs." The linchpin in question held the wheel on the gig and removing it made it likely that the wheel would come off as the vehicle moved. Such a pin was called a lynis in Old English; Middle English speakers added pin to form lynspin. By the early 20th century, English speakers were using linchpin for anything as critical to a complex situation as a linchpin is to a wagon, as when Winston Churchill, in 1930, wrote of Canada and the role it played in the relationship between Great Britain and the United States, that "no state, no country, no band of men can more truly be described as the linchpin of peace and world progress."

Examples of linchpin in a Sentence

This witness is the linchpin of the defense's case.

Recent Examples on the Web

Most of the people who carried the devices that exploded were probably field officers, the local linchpins for cells of fighters who make up the backbone of Hezbollah’s forces. —Ben Wedeman, CNN, 18 Sep. 2024

And a Duchenne muscular dystrophy treatment, the linchpin of the portfolio, failed to show any benefit in a large trial last month. —Elaine Chen, STAT, 26 July 2024

The linchpin of Milwaukee's freeway system sits just southwest where this week's historic events are taking place. —Caitlin Looby, Journal Sentinel, 17 July 2024

The Orioles shortstop has enjoyed a breakout season in 2024, emerging not just as a candidate for the American League Most Valuable Player Award but also as a linchpin for an organization that expects to be perennial playoff contenders for the foreseeable future. —Matt Weyrich, Baltimore Sun, 9 July 2024

Word History

Etymology

Middle English lynspin, from lyns linchpin (from Old English lynis) + pin; akin to Middle High German luns linchpin

First Known Use

13th century, in the meaning defined at sense 1

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Kids Definition

linchpin

noun

linch·​pin ˈlinch-ˌpin 

: a pin inserted crosswise through something (as the end of an axle or shaft) to keep things in place