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/)
I disagree with your premise. "Person" is a noun that identifies a single individual human being. "People", on the other hand, is a noun used for a collection consisting of "persons". "People" seems like a plural for "person" because in order to have a collection, one must necessarily have more than one. Because in many instances when one refers to multiple individuals it is not necessary whether to specify whether one is referring to the group or the individuals (three people standing on a street corner can be as accurately described as either "those three people over there" or as "those three persons over there"), people gets more usage than "persons", but people is not the plural of person. "Persons" is the word to use to specify more than one individual, when it is necessary or desirable to retain the reference to individuals.