A Marxist concept, largely synonymous with ‘society’, which refers to the institutional context which provides the conditions of existence of the mode of production. The term was devised by the structuralist Marxist Louis Althusser as a substitute for society, because he thought that the latter was too strongly marked by what he regarded as pre-Marxist humanist conceptions of social life as being (ultimately) the product of individual human beings. For this reason, its presence in a text normally indicates that the author works with a structuralist conception of social life, according to which social relations as such—rather than their bearers—are what determine what happens within societies. (It is worth noting that Marx himself rarely used the term.) For Althusser, a social formation is a complex of concrete economic, political, and ideological relations, bound together and given their particular character as capitalist, feudal, or whatever by the fact that the economic relations are, in his words, ‘determinant in the last instance’. Many of those who continue to use the term now reject this residual reductionism.