[...] calling capitalism a "mode of production" highlights the fact that there are other, different ways of organizing the social relations of economic life. Feudalism, which preceded capitalism in much of Europe, was one in which economic activity was organized by coercive lord-vassal relations of tribute and protection (and varied widely in the places and times historians call "feudal"). Another mode of production existed as the authoritarian "state socialism" of the former Soviet Union, a mode that most people erroneously call "communism" (largely because those systems misidentified themselves, of course; few would willingly call themselves "authoritarian state socialists").
footnote 2 explains why the USSR was not state capitalism, as some like to argue