They is used as a subject pronoun for people, animals, or things that are more than one. It is also widely used as a singular pronoun when a person’s gender is unknown, not specified, or nonbinary.
From Old Norse *þeir* 'they', which replaced Old English *hie* through language contact. English adopted the Norse set 'they/them/their' alongside its own older pronouns.
Singular 'they' feels modern, but English has used it for centuries in sentences like 'Someone left their bag; I hope they come back.' The fact that our 'they' comes from Norse shows how deeply English is a blended language.
“They” has been used as a singular pronoun in English for centuries, but 18th–19th century grammarians promoted generic ‘he’ and stigmatized singular ‘they,’ reinforcing male-default language. In recent decades, singular ‘they’ has been widely reaffirmed, including for nonbinary identities.
Use “they” as a singular, gender-neutral pronoun when a person’s gender is unknown, irrelevant, or nonbinary, and when that is their stated pronoun. This supports accuracy and respect without assuming gender.
["he or she (formal, now less preferred)"]
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