The name Dietrich is a boy's name of German origin meaning "ruler of the people". Dietrich and is often added to user-created lists like Awesome German Names and discussed in our forums with posts like "New: Movie Title Family Name Game!".
From the experts:
This form of Theodoric, familiar via Marlene, is a possible German import. It is an Anglicized ancestor of Derek and all its variations. A noted bearer was acclaimed classical German baritone and conductor Dietrich Fischer-Dieskau, and there have been Dietrichs in Henry James's The Princess Casamassima,/em and more recently on the TV show Psych.