The name Mattie is an American baby name. In American the meaning of the name Mattie is: Lady. French Meaning: The name Mattie is a French baby name. In French the meaning of the name Mattie is: Strong in war.erman Meaning: The name Mattie is a German baby name. In German the meaning of the name Mattie is: Strength in battle. Matilda was the wife of William the Conqueror.