Perhaps an alteration of an Italian dialect word, based on Latin sella 'saddle', from sedere 'sit'.

• saloon from early 18th century:

  Along with gunfights between goodies in white Stetsons and baddies in black ones, the saloon or bar is an important feature of Westerns. Like many an outlaw in the American West, people may sometimes have to drink at the last chance saloon, ‘take one final chance to get something right’. The name, sometimes expanded to First and Last Chance Saloon, was used in the US from about 1890 for the name of a saloon on the edge of town. The name was introduced to a wider public as the place that Frenchie, played by Marlene Dietrich, ran in the 1939 Western Destry Rides Again. Saloons (the word comes via French from Italian, from sala ‘hall’) were originally much more genteel than those on the wild frontier—the word at first applied to a large reception room or an elegant drawing room, as did salon (late 17th century), which has exactly the same source. Until many pubs were remodelled in the 1980s, most had a saloon bar, a separate area that was more luxuriously furnished and where drinks were more expensive than in the public bar. During the 19th century a saloon was a luxurious railway carriage used as a lounge or restaurant or for a private party. As the age of the car followed that of the train, a closed car with a separate boot came to be a saloon car in Britain. The American name, found from 1912 in this sense, is sedan, which was an Italian dialect word from Latin sella ‘seat’, also the source of saddle (Old English).