Question: I know pretty well that the plural for 'person' is 'people'. But my literature professor used once the word 'persons' because, he said, he was using the word the same as it will be used 'individuals'. Or at least I understood it that way. 

So, my question is: Can I use the word 'persons' in the next phrase? (I wrote the whole phrase in order for you to have the correct context.)

> 
> I'm so into the idea of developing each skill alike, the idea of being
>  round **persons**.
> 
> 
> 

Is it okay, or should I just use 'individuals'?

Thank you! :)

Answer: 
In general, the plural of "person" is "people". Exceptions include formal contexts such as law enforcement, and idiomatic phrases like "missing persons" or "persons unknown".

A historical prescription is to use "people" for an unspecified number of people, and "persons" for a specific number of individuals: "many people" but "three persons". However, this rule is no longer followed, and "people" is used for both cases.

In your example, I would use "people". (I would also suggest using "well-rounded" instead of "round", and using a more articulate phrase than "so into" to describe your interest.)

Sources:

* [Grammar Girl: People or Persons?](http://www.quickanddirtytips.com/education/grammar/people-or-persons)
* [Daily Writing Tips: People versus Persons](http://www.dailywritingtips.com/people-versus-persons/)
* [Grammarist: People vs. persons](http://grammarist.com/usage/people-persons/)
Your professor may be more or less correct about *persons*. 

To be upfront about it, I cringe every time I see the word, but in the hospitality industry they use *persons* specifically for individuals members of a group. Ten people arriving is ten people who have never met, but ten persons is a group of ten. The reason is that a group of ten persons will be treated differently to ten people in terms of rooming, checking in etc.

I suspect that this usage is what your professor was referring to.