An Etymological Dictionary of the German Language/Annotated/sie

by Friedrich Kluge

sie, pronoun, ‘she, her, it, they, them’; from Middle High German sie, si (sî), nominative and accusative singular feminine, nominative and accusative plural, masculine, feminine, and neuter, Old High German siu, sī̆, nominative singular feminine, sié, nominative and accusative plural. For further details see grammars.