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

In this new reality, the most successful CMOs will be those who recognize and empower their insights teams as the linchpin of their strategic initiatives, turning data into a powerful force that underpins every decision. —Nataly Kelly, Forbes, 15 Oct. 2024

Sequels and reboots and rereleases may be the linchpins of Hollywood’s nostalgia-industrial complex, but goth’s comeback goes beyond the reanimation of dormant titles. —Judy Berman, TIME, 10 Oct. 2024

It’s taken decades of painstaking effort to rebuild America’s profitable steel industry, beat back unfair trade practices by countries like China and Japan, and position domestic steelmaking as a linchpin of U.S. national security. —David McCall, Fortune, 4 Oct. 2024

The alleged linchpin of the October surprise was William Casey, Reagan’s campaign manager through most of 1980. —Gal Beckerman, The Atlantic, 2 Oct. 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

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