# EN: focus - plural: focuses / foci



## gman67

Hi,

I've got  a simple question. Is it focus or focuses when this word is in pluriel?

Thank you,

Gilles


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## marget

Focuses and foci can both be used.  The first one is more common.


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## Tresley

It's the same in the UK. (I noticed that you are in Liverpool).

Both 'focuses' and 'foci' are used as the plural for 'focus', but 'focuses' is more common.

I hope this helps.


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## wildan1

_foci_ is logically the plural of the word considering its Latin origin (pronounced _FOK-eye_), but sounds a bit pretentious, imo.


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## cropje_jnr

_Foci_ for academic literature, _focuses _in all other contexts, as a general rule (much like _forums _and _fora_).


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## Angle O'Phial

Foci (pronnounced, for me anyway, FOS-eye; Mirriam-Webster lists both pronunciations) is common in mathematics. An ellipse, for example has two foci. It would be odd to say that an ellipse has two focuses.


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## johndot

Many people uses both plurals; one when discussing scientific subjects, the other when not.


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## Tresley

I think that both Cropje_jnr and Angle O'Phial have a point here.

Gman67 ... this isn't a simple question at all!

It depends on the context! Would you provide a sentence please?

I too now think that for an academic translation, you ought to use 'foci' (maths, physics, optics etc), but for anything else use 'focuses'.

For example: 

'The main focuses of attention are as follows:' (i.e. non academic context).

I hadn't thought about the academic usage. Cropje_jnr and Angle O'Phial are both quite right.

However, I would never dream of saying 'cactuses' as the plural of 'cactus', it's always 'cacti'!

I hope this helps.


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## wildan1

science vs. non-science context--interesting insight on Latin plurals in English


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## Tresley

Yes, I now think there is a distinction, but I don't know why.

The expression 'nuclear foci' popped into my head (academic/scientific).

I think that Cropje_jnr and Angle O'Phial are both quite right.

Wildan, don't you agree?


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## wildan1

I'm not a hard scientist--but work in the social sciences/humanities. When I hear colleagues say _"foci"_ it strikes me that they are showing off. But I don't go to science conferences...


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## Tresley

Hi Wildan ,

I'm not a scientist either, but I did wonder why, in some contexts 'focuses' is used, and in others 'foci' is used. I know that 'focuses' is the more common term, however, I now think that 'focuses' sounds very wrong in an academic context.

I didn't realise this distinction until Cropje_jnr and Angle O'Phial pointed this out and I think that they are both right.

Would anyone else like to comment?


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## gman67

Thanks you all for your great help. I was enquiring for the non-academic term which is focuses.

thank again

Gilles


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## Anon255

Sorry for being late to the party but I completely disagree. 

Focus can be either a noun or a verb.

The plural can ONLY be foci. 

Focuses is a conjugation of the VERB to focus. 

So I can say: This research focuses...(even in an academic setting)

Or I can say, the foci of this research... (assuming it has more than one focus). 

There are no other options and the setting (academic or not) is irrelevant.

To be fair, the latter is more appropriate as research "focusing," is a bit of a personification.


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## Tresley

The Cambridge dictionary clearly states that both plurals are used (*focuses and foci*), but *foci* is formal.

http://dictionary.cambridge.org/dictionary/british/focus_1?q=focus

The Oxford Dictionary also says that both are used, but does not specify any formal usage of foci.

http://oxforddictionaries.com/definition/focus?q=focus 

Dictionary.com also says that both plurals are acceptable

http://dictionary.reference.com/browse/focus

I hope this helps.


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## Bob Burke

As an academic for many years I always read the word 'foci' and never heard anyone say it.  I would reformulate my sentences to avoid it because I couldn't bear to say it, but didn't want to be laughed at for saying 'focuses' as the plural.  Now I don't care, so 'focuses' it is for me!

'Foci' is OK for people who say 'cacti' and 'octopi'.

In my opinion, we are speaking English, not Latin.

PS We have no idea how Latin was pronounced. I have just asked a friend of a Latin persuasion and 'foci' would not be FOLK-eye, FOK-eye or FOSS-eye, but FOCHEE. I'll leave that debate here and return to my various focuses on English phonology...


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## Maître Capello

In scientific contexts, when talking about a lens or ellipse, you only say _foci_. _Focuses_ would be very unusual in those contexts.

PS


Bob Burke said:


> PS We have no idea how Latin was pronounced. I have just asked a friend of a Latin persuasion and 'foci' would not be FOLK-eye, FOK-eye or FOSS-eye, but FOCHEE. I'll leave that debate here and return to my various focuses on English phonology...


Actually, we do know how Latin was pronounced – namely "fok-ee", not "fok-eye" – but I'm afraid this is outside the scope of this forum, which only deals with French and English.


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## dragonbones

Both plurals, foci and focuses, are in common usage. In non-academic, non-scientific use ‘focuses’ is probably more colloquial, and foci may come across as pretentious. However, in formal and academic usage (math, science, etc.) foci predominates (in some contexts it is the only choice, e.g. an ellipse has two foci, as *Angle O'Phial *noted).

 In humanities and social science writing and in an introduction to a research center, both seem acceptable to me, but if forced to choose, I’d lean toward foci, as usage of Latin plurals seems more erudite; but consider your audience when choosing. In the latter context consistency is probably more important than which one is chosen.


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