"Duce is an Italian word meaning leader or the second, derived from Latin word dux in singular accusative case "ducem" which means to lead, of which Duke is a derivation. Other Italian leaders whose names derive from dux are the Doges of Venice and Genoa, and the title of nobility duca ("duke")....
Due to Benito Mussolini, who gave himself the name "Il Duce" in 1925, it has become associated with Fascism and is no longer frequent in contemporary use other than in reference to him....Due to modern anti-fascist sentiment, Italian speakers in general now use other words for "leader.""
"Duce," from the same Latin root as "duke," is Italian for "leader." Before Mussolini, both King Victor Emmanuel III and Gabriele d'Annunzio used the title.
https://en.wikipedia.org/wiki/Duce
