Definition of "they" [they]

• Used to refer to the ones previously mentioned or implied. (pronoun)
• Usage Problem Used to refer to the one previously mentioned or implied, especially as a substitute for generic he: Every person has rights under the law, but they don't always know them. See Usage Note at he1. (pronoun)
• Used to refer to people in general. (pronoun)
• Used to refer to people in general as seen in a position of authority. (pronoun)
• Refers to people or things other than the speaker or people addressed (pronoun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• Refers to unspecified people or people in general not including the speaker or people addressed (pronoun)
• Refers to an indefinite antecedent such as one, whoever, or anybody (pronoun)

www.Collinsdictionary.com (c) HarperCollins Publishers Ltd 2016

• " When they come back,  they pay the hotel sitter, then ask you to sit down and tell you in their nice voices that Jesus has come and Grandma is gone."
• "  If they do not start making serious moves towards cutting their deficit,  they are next for a test."
• "No one here is really saying they do — problem is that *they* are expecting/demanding non Mexican Americans to give up *theirs* for a day."