them1 S1 W1 [object form of 'they']
used to refer to two or more people or things that have already been mentioned or are already known about:
Has anyone seen my keys? I can't find them anywhere.
The police were very helpful when I spoke to them.
I lent him several books, but he hasn't read any of them.
used when talking about someone who may be male or female, to avoid saying 'him or her':
If anyone phones, tell them I'll be back later.