bour·geois1 /bʊərˈʒwɑ, ˈbʊərʒwɑ; Fr. burˈʒwa/

–noun

1. a member of the middle class.
2. a person whose political, economic, and social opinions are believed to be determined mainly by concern for property values and conventional respectability.
3. a shopkeeper or merchant.
–adjective
4. belonging to, characteristic of, or consisting of the middle class.
5. conventional; middle-class.
6. dominated or characterized by materialistic pursuits or concerns.

Bourgeoisie is used to describe a social class of people whose status or power comes from employment, education, and wealth as opposed to aristocratic origin.
Petite bourgeoisie (also Petty Bourgeoisie) is used to describe the class below the bourgeoisie but above the Proletariat.

In the French feudal order pre-revolution, "bourgeois" was a class of citizens who were wealthier members of the Third Estate, but were overtaxed and had none of the privileges which the aristocracy held (however many bourgeoisie bought their way into nobility; see Venal Office).

"It is better to be a good ordinary bourgeois than a bad ordinary bohemian."
[Aldous Huxley, 1930]

As an adjective it is used with contempt by bohemians and Marxists to label conservatives whose views are not sufficiently revolutionary