Diederich is a German variant of the name Dietrich, which itself is derived from the Old High German name Theodoric. The name Theodoric is composed of the elements 'theud', meaning 'people' or 'folk', and 'ric', meaning 'ruler' or 'power'. Thus, Diederich carries the meaning of 'ruler of the people' or 'leader of the folk'. The name has been used both as a given name and a surname in German-speaking regions.