pronoun

 

group used as the subject of the verb when referring to a group of people, animals, or things that have already been talked about

I saw Kate and Nigel yesterday - they came over for dinner.

 

person used to refer to a person when you want to avoid saying 'he' or 'she' or when you do not know if the person is male or female

Someone I met at a party said they knew you.

 

people people in general

They say that breaking a mirror brings you seven years' bad luck.