cotter pin

American  

noun

Machinery.

1. a cotter having a split end that is spread after being pushed through a hole to prevent it from working loose.

---

cotter pin British  

noun

1. a split pin secured, after passing through holes in the parts to be attached, by spreading the ends

2. a tapered pin threaded at the smaller end and secured by a nut after insertion

---

Etymology

Origin of cotter pin

First recorded in 1890–95

Example Sentences

As the U.S. cotter pin in the United Nations, Lodge was given Cabinet status and a large voice in U.S. policy�and grew in stature to measure up to both.

From Time Magazine Archive

At the Mikawa mine on southern Kyushu island, a cotter pin apparently fell out of a coupling on a string of coal cars halted on a slight incline.

From Time Magazine Archive

The cause of the accident was narrowed down to a cotter pin, which one of the mechanics at Valbuena Field had forgotten to replace after greasing the landing wheels that morning.

From Time Magazine Archive

Serial writers ran out of hazards years ago, have been working switches on them ever since; the loose cotter pin on the stagecoach, for example, has been used an estimated 7,000 times.

From Time Magazine Archive

The washer F is held tightly against the hook by pressure from a spring, G. The spring is held in place by a small nut, H, and cotter pin, 1.

From The Boy Mechanic: Volume 1 700 Things for Boys to Do by Popular Mechanics Co.