their
UK: ðeə(r) | US: ðer
adj. belonging to or associated with the people or things previously mentioned or easily identified
adj. used to refer to a person of unspecified gender (singular 'they')
The word "their" originates from Old Norse þeirra, the genitive plural form of þeir ("they"). It was adopted into Middle English to replace the Old English hiera, streamlining the pronoun system. The final -r reflects its Norse inflectional ending. Over time, it lost its case-marking function but retained the spelling. In modern usage, "their" also serves as a gender-neutral singular possessive pronoun, adapting to evolving linguistic needs.
The students forgot their textbooks in the classroom.
Their house is at the end of the street.
Someone left their umbrella on the bus.
The team celebrated their victory with a party.
Each participant must submit their application by Friday.