The landed, noble class. During the feudal stage of economic development, the aristocracy was comprised of the owners of the means of production. 

The members of the ruling class in the capitalist system, distinguished from the proletariat by their ownership of property and their ability to amass capital. “Bourgeois” can be used as a noun or an adjective, while “bourgeoisie” can be used only as a noun to refer to the entire class. 

The surplus value generated by the wage laborer for the capitalist. This profit is reinvested by the capitalist to buy more materials, labor, etc. to produce more profit, with a snowballing effect that benefits the capitalist, but not the worker.