The bourgeoisie are a class of business owners and merchants which emerged in the Late Middle Ages, originally as a "middle class" between peasantry and aristocracy.

~~It is possible that the meaning of "middle class" has changed. So Musk is middle class, but the lawyer or pizza shop owner are not.~~

Edit: shit, I should have read farther. Bourgeois is used in multiple ideologies.

https://en.m.wikipedia.org/wiki/Communism

The two classes are the proletariat, who make up the majority of the population within society and must sell their labor power to survive, and the bourgeoisie, a small minority that derives profit from employing the working class through private ownership of the means of production.