There are five main Mafia groups in Italy: Cosa Nostra based in Sicily, Camorra from Naples, Ndranghetta in Calabria, Stidda, also based in Sicily, and Sacra Corona Unita of Puglia. Although the last two groups are relatively new, the first three began operating sometime between 1500-1800. Today we use other names to refer to the Mafia, for instance, the Mob. According to the Online Etymology Dictionary the word “mob” entered the vocabulary in 1680 as the "disorderly part of the population, rabble," and went on to mean a "gang of criminals working together" in 1839, and from there "organized crime in general" in 1927 in the US. After 1927, the Mob became synonymous with the Mafia.