An Etymological Dictionary of the German Language/Annotated/du

du, 2nd personal pronoun, ‘thou’; from Middle High German and Old High German du, and the collateral Middle High German and Old High German ; compare Anglo-Saxon þû, English thou; Latin tu, Greek τύ, σύ, and Sanscrit tvam, are primary cognates. The details respecting the Aryan pronominal stem belong to grammar.