Boss (Dutch, baas, master, perhaps originally uncle; cf. German, base, aunt or female cousin). In American slang, a master or employer of labour - in this sense, no doubt, derived from the Dutch settlers in what was afterwards New York state. Also, the wire-puller of a political organisation. "Boss Tweed," the leader of the corrupt and infamous Tammany Ring, was a familiar figure in New York municipal politics in 1871.