Final answer:
The word 'proletariat' refers to the working class, specifically in a capitalist society, where they sell their labor but do not own the products of their labor.
Step-by-step explanation:
The meaning of the word 'proletariat' is option 1) Working class. The term proletariat originated from Roman law, referring to a class of citizens who were essentially propertyless except for their children. In a capitalist society, the concept evolved to signify those who have no means of production of their own and are reduced to selling their labor power in order to live. Karl Marx, a central figure in the development of socialism and communism, defined the proletariat as the industrial working class, who were exploited by the bourgeoisie, the owning class. Marx detailed that the proletariat was oppressed and alienated in the capitalist system, as the fruits of their labor benefitted the capitalists while the workers received only a wage and suffered from the separation from the the products they created and a loss of control over their labor.