Definitions

1. pronoun

used to refer to people or things previously mentioned or easily identified

“The teacher asked the students to take out their books, and they began to read.”

2. pronoun

used to refer to people or animals in general, or to a group of people

“They are a happy family.”

3. pronoun

used to refer to a person or people who are not specified, but are implied to be of a particular type or group

“Someone has left their umbrella on the bench.”

4. verb

past tense of ‘to be’ used as a linking verb

“They are coming over tonight.”