their

Where does the word "their" come from? It comes from Old Norse þeirra, passing through Middle English before entering English (1400s).

Their’s story begins in Old Norse: þeirra meant “of them.” Genitive plural of the demonstrative 'sá', 'that one'. By 1200s, the word had taken hold in Middle English as þeir. Spread south from the Danelaw, replacing Old English 'hiera', which sounded too close to 'her'. It reached English by 1400s as their. A rare case of a core pronoun borrowed from another language, reaching London English last. Today, their means belonging to or associated with them.

1. Stage 1 · Old Norse · medieval þeirra "of them", genitive plural of the demonstrative 'sá', 'that one'.
2. Stage 2 · Middle English · 1200s þeir "belonging to them", spread south from the Danelaw, replacing Old English 'hiera', which sounded too close to 'her'.
3. Stage 3 · English · 1400s their "belonging to them", a rare case of a core pronoun borrowed from another language, reaching London English last.