Short answers, pulled from the story.
Karl Marx defined the working class, or proletariat, as those who possess nothing to sell but their labor power. This definition establishes a clear dichotomy between wage laborers and those who live on accumulated capital.
The English working class emerged as a distinct political entity before the late eighteenth century during the transformation of pre-modern laboring classes. E. P. Thompson argued in The Making of the English Working Class that this group was present at its own creation.
Sociologist Mike Davis coined the term informal working class to describe a global phenomenon that has developed worldwide since the 1960s. These individuals exist outside the formal economy and predominantly live in slums in the southern hemisphere.
China, Laos, Vietnam, and Cuba adopted Soviet-style societies starting around 1917 to rule in the interests of the working class. North Korea also turned inwards into an increasing cycle of poverty and brutalization during this period.
Diane Reay highlighted that working-class students face profound challenges due to the university community being perceived as a predominately middle-class social space. This creates a sense of otherness and structural barriers regarding access to economic resources and cultural interests.
The New York Times has loosely defined the white working class as comprising white people without college degrees. This definition highlights the intersection of race and class in American society.