What is "singular they"

n. (context grammar English) The use of ''they'' to agree to with a singular antecedent as in the sentence "Everyone said they knew what they were doing."

Singular they is the use in English of the pronoun they, or its inflected or derivative forms, such as them, their, themself, or themselves, as a gender-neutral pronoun to refer to a single person or an antecedent that is grammatically singular. It typically occurs with an antecedent of indeterminate gender, as in sentences such as:

• "Somebody left their umbrella in the office. Would they please collect it?"
• "The patient should be told at the outset how much they will be required to pay."
• "But a journalist should not be forced to reveal their sources."

The singular they had emerged by the 14th century and is common in everyday spoken English, but its use has been the target of criticism since the late 19th century. Its use in formal English has increased with the trend toward gender-inclusive language.