A masquerade, in the seventeenth and eighteenth centuries, was a masked ball, where participants would wear masks, and often adopt elaborate costumes. Masquerades adopted some of the characteristics of carnival, but were organised as commercial undertakings. Like carnival, they came to be associated with licence and moral depravity and died out in the new moral seriousness that began to appear in Western society in the late eighteenth century.
Venice became famous among fashionable aristocratic society in the eighteenth century for its often decadent masquerade parties during carnival week (prior to Lent). In modern Venice, carnival week is still celebrated by performers in the streets with masks and period costumes, and this is a major tourist attraction.
In modern parlance a masquerade is a sham: a performance - often associated with politics - put on to deceive the observer.