Definition of cotter pin in English:

cotter pin

(also cotter)

Pronunciation /ˈkädər ˌpin/ /ˈkɑdər ˌpɪn/

Translate cotter pin into Spanish


  • 1A metal pin used to fasten two parts of a mechanism together.

    ‘She slid the cotter pin back through the nut and bolt and screwed the grease cap back on.’
    • ‘A cotter pin acts a safety measure to prevent the arm from sliding off the stub.’
    • ‘The cotter pin missed the male spline on the flap motor.’
    • ‘The investigation revealed maintainers had left out a cotter pin on the main-landing-gear-door strut.’
    • ‘Both corded and cordless benders, cotters, and combination benders/cutters are now light enough to carry around all day.’
    • ‘So I stood there in three feet of icy water, barking my knuckles bloody using a closed pocketknife to pry back the ears of the cotter pin so I could remove the prop nut, prop, and get to the broken shear pin.’
    • ‘At this point the wire should look like a cotter pin.’
    • ‘If it's not in stock, even a simple cotter pin can take weeks to get.’
    • ‘Once in a while some suburban dad would walk in with a cotter pin and say ‘I need three more of these, ‘and I'd go in the back and hunt around for them.’
    • ‘I tried to use the mower as I'd done the previous week, but this time I snapped a cotter pin, and had to find another one to hold the handle in place.’
    • ‘A removable cotter pin holds the plate securely in either mode.’
    • ‘‘A little pain and deprivation adds piquancy,’ he said, placing the last of the poles and threading its cotter pin home with a snap.’
    • ‘He noticed a nut and cotter pin were missing from the shroud-roller bearing assembly.’
    • ‘Crewmembers tend to use whichever bolts, pins, washers, or cotter pins they find in their spare-bolt bins to hold together this portion of the plow.’
    • ‘Use cotter pins through the axle on both sides and washers on either side of each wheel to keep the wheels from running off when you turn corners.’
    • ‘Lastly, multiple foreign objects were found throughout the wing: line caps, castellated nuts, washers, and cotter pins.’
    • ‘Heavy-duty cotter pins are long cylinder shaped pins with locking action provided by a ring mounted on the head of the pin.’
    • ‘The diagonal cutting pliers are designed for cutting wire and cotter pins close to a flat surface and are especially useful in the electronic and electrical fields.’
    • ‘Following manufacturers' instructions, check the wheel bearings for condition and wear and, if needed, repack with new seals and cotter pins.’
    • ‘Simpler ox bow keys were made either like rather crude keys with a flat bit or somewhat like oversized cotter pins.’
    1. 1.1A split pin that is opened out after being passed through a hole.


Mid 17th century of unknown origin.