# Inverted or inversed. Grammar help

1. Dec 26, 2015

### Barclay

1. The problem statement, all variables and given/known data
When viewing an image in a plane mirror do we say the image is laterally inversed or laterally inverted or there is lateral inversion.

I've seen laterally inverted written in a book though to me inverted means upside down. Though I do understand laterally means sideways so laterally inverted means 'upside down sideways'. A bit messy explanation.

I've seen the phrase there is lateral inversion on the Internet and this sounds good.

I want to say just simply that the image in the mirror is laterally inversed but Google does not recognize the word inversed but a dictionary does recognize inversed as a word.

Inverse is like an inverse function; sounds like reverse function so maybe is this the best word.

2. Relevant equations

3. The attempt at a solution

2. Dec 26, 2015

### Staff: Mentor

Not laterally "inversed." To the best of my knowledge, "inversed" is not a word in the English language.

3. Dec 26, 2015

### phinds

"inversed" is not a word in english. "Inversion" is. You can check these things trivially on Google. Just say "define <word of your choice>"

EDIT: I see Mark beat me to it.

4. Dec 26, 2015

### Barclay

5. Dec 26, 2015

### phinds

I'll be darned. I've never seen it used anywhere. I'd suggest checking a reliable printed dictionary such as the Oxford unabridged, and even if it's there, I wouldn't use it. Just SOUNDS wrong.

EDIT: I just checked Oxford online. I was right in the first place. It's not a word. Unreliable sources give unreliable results.

6. Dec 26, 2015

### Barclay

Okay I'll use the word inverted but that sounds wrong too when describing the image in a plain mirror. "The image in the mirror is laterally inverted".
Inverted sounds to mean upside down. Adding laterally to inverted appears to suggest the image is upside down and sideways reversed.
But I'll stick to the rules and say inverted and forget inversed.

Is it better / okay to say "... laterally reversed"

7. Dec 26, 2015

### phinds

No, it means put upside down OR "put in the opposite direction". It is absolutely correct in this usage.

8. Dec 26, 2015

### Staff: Mentor

I can't say I've ever heard "inversed" used, though I don't see anything hindering its usage. If you can popularise its use, it will become legit!

Well, I'm saying I've heard much worse allowed. "Irregardless," for example. :-)

9. Dec 26, 2015

### Staff: Mentor

I've taught optics at the first-year level from various textbooks, and at the upper-division undergraduate level from three textbooks (Hecht, Meyer-Arendt and Pedrotti3), over a period of almost 30 years. I don't ever remember ever seeing "inversed" used to describe an image (or object), only "inverted".

Mind you, I'm in the US, and all of my textbooks were published in the US. Perhaps in the UK, or in some UK-influenced country (ahem ), "inversed" is used in this sense.

10. Dec 27, 2015

### Staff: Mentor

For the visual appearance of a mirror image, "reversed" is the usual common description. "Laterally reversed" is OK if you want to be more specific for some reason.

I hope you're aware that such an image is not actually reversed laterally, but instead it's reversed front-to-back. See the following thread, in particular posts #8 and #19:

11. Dec 27, 2015

### Barclay

12. Dec 27, 2015

### Mister T

I have seen "perverted" used in textbooks to describe the image in a plane mirror. I wouldn't use "inverted" as that is typically used to mean a reversal in an absolute direction (e.g. up is inverted to down, east is inverted to west). Plane mirrors don't invert images in this way.

13. Dec 28, 2015

### Barclay

So you agree with me that laterally inverted sounds wrong.

Inversed in not a dictionary word.

Therefore shall we all start using laterally reversed ??? Is that a good description of the action of a plane mirror?

14. Dec 28, 2015

### Mister T

I don't think it as descriptive as left-right reversed.