cotter pin

noun

: a half-round metal strip bent into a pin whose ends can be flared after insertion through a slot or hole

Examples of cotter pin in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
When properly installed, the bolts have a metal cotter pin in place meant to keep them from completely backing out. — Evan Simko-Bednarski, New York Daily News, 29 Jan. 2024 People detained on cutters have swallowed jagged metal cotter pins pulled from the rigging and stabbed themselves with smuggled blades, apparently trying to cause such severe injury that they’d be taken to a hospital. — Seth Freed Wessler, ProPublica, 11 Dec. 2023

Word History

First Known Use

1881, in the meaning defined above

Time Traveler
The first known use of cotter pin was in 1881

Rhymes for cotter pin

See All Rhymes for cotter pin

Browse Nearby Words

cotter mill
cotter pin
cotterway
See all Nearby Words

Cite this Entry

“Cotter pin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cotter%20pin. Accessed 29 Mar. 2025.

Copy Citation

Share

Kids Definition

cotter pin

noun
: a half-round metal strip bent into a pin whose ends can be spread apart after insertion through a slot or hole

More from Merriam-Webster on cotter pin

Britannica.com: Encyclopedia article about cotter pin

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

Words You Always Have to Look Up

Democracy or Republic: What's the difference?
See More

Popular in Wordplay

See More

Top 10 Sophisticated Insults

Flower Etymologies For Your Spring Garden

More Words with Remarkable Origins

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments
See More

Popular

See More

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Top 10 Sophisticated Insults

Flower Etymologies For Your Spring Garden
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
burrowing owl athene cunicularia tilts its head outside its burrow on marco island florida
Guess the Curious Origins of These Everyday Words Oh, that’s where that comes from…
See All