What Is the Singular They?
They is a third-person pronoun, usually referring to a group of something.
It is possible, however, to use they in reference to a single something (the same is true for the possessive, objective, and reflexive forms of they: their, them, and themselves). This is sometimes called the singular they.
You can see the singular they in action in the example above. This sentence also demonstrates a common reason people reach for the singular they in both writing and speech: English has no gender-neutral third-person singular pronoun that can be used for talking about people. (Referring to a person as it is derogatory). In the sentence above, the gender of the teacher is unknown; it’s also irrelevant. You might even argue that it doesn’t really exist, because we’re not talking about any particular teacher. We’re talking about teachers in general. See More . . .