(the third-person plural) A group of people, animals, plants, or objects previously mentioned.
‘Fred and Jane? They just arrived.’; ‘Dogs may bark if they want to be fed.’; ‘Plants wilt if they are not watered.’; ‘I have a car and a truck, but they are both broken.’;
A single person, previously mentioned, especially if of unknown or non-binary gender, but not if previously named and identified as male or female.
(indefinite pronoun, vague meaning) People; some people; people in general; someone, excluding the speaker.
‘They say it’s a good place to live.’; ‘They didn’t have computers in the old days.’; ‘They should do something about this.’; ‘They have a lot of snow in winter.’;
There especially as an expletive subject of be.
The plural of he, she, or it. They is never used adjectively, but always as a pronoun proper, and sometimes refers to persons without an antecedent expressed.
‘Jolif and glad they went unto here [their] restAnd casten hem [them] full early for to sail.’; ‘They of Italy salute you.’; ‘Blessed are they which do hunger and thirst after righteousness.’;
used to refer to two or more people or things previously mentioned or easily identified
‘the two men could get life sentences if they are convicted’;
people in general
‘the rest, as they say, is history’;
people in authority regarded collectively
‘they cut my water off’;
used to refer to a person of unspecified gender
‘ask a friend if they could help’;
In Modern English, they is a third-person pronoun.