'partner' originates from Middle English, specifically the word 'partener,' where 'part' meant 'portion' and '-ner' was a suffix indicating a person involved.

'partener' changed from the Old French word 'parçonier' and eventually became the modern English word 'partner'.

Initially, it meant 'one who shares,' but over time it evolved into its current meaning of 'a person who takes part in an undertaking with another.'