The name Reginald is a German baby name. In German the meaning of the name Reginald is: Powerful ruler. American Meaning: The name Reginald is an American baby name.In American the meaning of the name Reginald is: Powerful ruler.Teutonic Meaning: The name Reginald is a Teutonic baby name.In Teutonic the meaning of the name Reginald is: Strong judgment. English Meaning: The name Reginald is an English baby name.In English the meaning of the name Reginald is: Mighty counselor-ruler.he name Reginald is an American baby name. In American the meaning of the name Reginald is: Powerful ruler. Teutonic Meaning: The name Reginald is a Teutonic baby name.