# English usage question: -or vs. -er

**URL:** <https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518>\
**Category:** Factual Questions\
**Created:** [April 28, 2005, 10:43am UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518 "2005-04-28T10:43:19Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Greg\_Charles](https://avatars.discourse-cdn.com/v4/letter/g/839c29/32.png) [@Greg\_Charles](https://boards.straightdope.com/u/Greg_Charles)\
**Post date:** [April 28, 2005, 10:43am UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518/1 "2005-04-28T10:43:19Z")

</div>

Adding -er or -or to a verb generally makes a noun with the meaning of someone or something that performs that action. Is there any way to know which one to use?

I’m using a computer, so that makes me a computor. However, I can also be a processor, and the computer uses a processor. The job of one machine I worked with was to modulate, so it was a modulator; another’s job was to scramble, so it was a scrambler. What about a machine used to encrypt? Is it an encryptor or an encrypter? Would a person doing the job be different? My head spinning. (It’s a spinner?)

---

<div class="post-metadata">

**Author:** ![woodstockbirdybird](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/woodstockbirdybird/32/7905_2.png) [@woodstockbirdybird](https://boards.straightdope.com/u/woodstockbirdybird)\
**Post date:** [April 28, 2005, 11:24am UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518/2 "2005-04-28T11:24:46Z")

</div>

That’s a good question. I don’t know the answer, and I can’t see any logical rule jumping out at me, but I have noticed that here in the U.S. we spell the word “impostor”, while Elvis Costello (who’s from the UK; I’m just assuming this holds for UK spelling in general) spells it “imposter”. Which I always found odd for some reason. Sorry for the hijack. Maybe it holds a clue.

---

<div class="post-metadata">

**Author:** ![TheLoadedDog](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)\
**Post date:** [April 28, 2005, 11:27am UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518/3 "2005-04-28T11:27:36Z")

</div>

I’m not sure what the rule is. Whatever it is, it’s probably reasonably flexible to account for the different international usages: US English seems to have more “-er” words and fewer “-or” words than Commonwealth English (adapter/adaptor).

---

<div class="post-metadata">

**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\
**Post date:** [April 28, 2005, 12:15pm UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518/4 "2005-04-28T12:15:55Z")

</div>

I don’t believe there is any rule. People pick one or the other until a common usage is determined.

---

<div class="post-metadata">

**Author:** ![Kizarvexius](https://avatars.discourse-cdn.com/v4/letter/k/da6949/32.png) [@Kizarvexius](https://boards.straightdope.com/u/Kizarvexius)\
**Post date:** [April 28, 2005, 7:08pm UTC](https://boards.straightdope.com/t/english-usage-question-or-vs-er/301518/5 "2005-04-28T19:08:51Z")

</div>

My rule of thumb is this:

If the word is of Greek or Latin origin, use -or as the suffix.  
If the word is of Germanic origin, use -er.

It’s not foolproof by any means, but it works for me.