De" of is a German phrase meaning "of" or "belonging to". It is used to indicate possession or ownership of something. It can also be used to denote a relationship between two things. For example, "Der Mann de Frau" means "the man of
From Wikipedia
Daniel Michael DeVito Jr., is an American actor and filmmaker. Known for his short stature, raspy voice, distinct accent, and energetic comedy roles, he gained prominence for his portrayal of the taxi dispatcher Louie De Palma in the television series Taxi (1978–1983), which won him a Golden Globe Award and an Emmy Award. Since 2006, he has played Frank Reynolds on the FX/FXX sitcom It's Always Sunny in Philadelphia.