# Terminology : Dome nuts v. Acorn nuts

**URL:** <https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342>\
**Category:** Factual Questions\
**Created:** [May 25, 2013, 8:52pm UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342 "2013-05-25T20:52:35Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Bones\_Daley](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@Bones\_Daley](https://boards.straightdope.com/u/Bones_Daley)\
**Post date:** [May 25, 2013, 8:52pm UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342/1 "2013-05-25T20:52:35Z")

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Now, I have plenty of experience in the fastener field, and my business involves buying multiple quantities of what I have always termed “dome nuts”, but I do understand that these nuts can also be termed “acorn nuts” (and also “cap nuts”) .

So, is the difference in terminology purely geographical …is it the case that the US might prefer to term these nuts “acorn nuts” , and that the UK prefer the term “dome nuts” ?

Or does the “acorn nut” terminology embrace other types of nuts such as “split domes” which expand to accommodate excess threaded rod, whereas “dome nuts” indicate a totally sealed cap ?

I do apologise in advance for starting what might just be the most boring thread ever on this forum …

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [May 26, 2013, 12:17am UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342/2 "2013-05-26T00:17:03Z")

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i first heard them called acorn nut and later cap nut, split or solid.

it is often a locking nut.

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**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\
**Post date:** [May 26, 2013, 12:20am UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342/3 "2013-05-26T00:20:50Z")

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I have never seen a locking acorn nut. I have never heard an acorn nut called a dome nut.  
YMMV

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**Author:** ![Bones\_Daley](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@Bones\_Daley](https://boards.straightdope.com/u/Bones_Daley)\
**Post date:** [May 26, 2013, 11:27am UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342/4 "2013-05-26T11:27:03Z")

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> [@Rick](#):
>
> I have never seen a locking acorn nut. I have never heard an acorn nut called a dome nut.  
> YMMV

I’m assuming that it is a geographical thing, then.

Googling “dome nuts” brings up almost 7,000,000 hits, and “acorn nuts” gets just over 2,000,000 so I am deducing from that (possibly mistakenly) that world-wide,  
“dome nuts” is the more common term.

I \*\*\*did \*\*\*say this was a boring thread …☹

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [May 26, 2013, 2:07pm UTC](https://boards.straightdope.com/t/terminology-dome-nuts-v-acorn-nuts/659342/5 "2013-05-26T14:07:15Z")

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if you were asking about twist bits it would be boring. this thread was encapsulating.