Dictatorship of the proletariat. It doesnt mean dictatorship as its widely used today, just as a description of which class is on top. Marx described every capitalist and feudalist state as a dictatorship of the bourgois/capital so its used to indicate what class is in controll of the state and society . So a dictatorship of the proletariat more or less the period that follows a revolution with the working class taking hold of the state and power, recreating it with a new class character and supressing the burgeois and and reactionaries