Radu R. Florescu

“When he eventually returned to his native country, Vlad was called “Dracul” by the boyars, who knew of his honor, because he was a Draconist, a member of the Order of the Dragon (draco in Latin), dedicated to fighting Turks and heretics. On the other hand, the people at large, unfamiliar with the details of Vlad's investiture in the order, seeing a dragon on his shield, and later on his coins, called him “Dracul” with the meaning of the “devil,” because in Orthodox iconography, particularly those ikons that depicted St. George slaying a dragon, the dragon symbolized the devil. The word drac (-ul is simply the definite article “the”) can mean both “devil” and “dragon” in the Romanian language. It is important also to underscore the fact that, at the time, the use of this particular nickname in no way implied that Dracul was an evil figure, in some way connected with the forces of darkness, as some have suggested. The name Dracula, immortalized by Bram Stoker, was later adopted, or rather inherited, by Dracul's son. Dracula, with the a, is simply a diminutive, meaning “son of the dragon.” (The son inherited the title Dracul by virtue of the statutes of the order.) Evil implications were attached to the name only much later by Dracula's political detractors, who exploited its double meaning.”
― Radu R. Florescu, Dracula, Prince of Many Faces: His Life and His Times